diff --git a/ansible/host_vars/monerod_box_local/main.yml b/ansible/host_vars/monerod_box_local/main.yml
index 181beb1..5a1b130 100644
--- a/ansible/host_vars/monerod_box_local/main.yml
+++ b/ansible/host_vars/monerod_box_local/main.yml
@@ -29,3 +29,24 @@ monero_data_device: /dev/sdb
 monitored_services:
   - monerod
   - xmrblocks
+
+# ...but on THIS host, once a day rather than every five minutes.
+#
+# Both units are a Monero node in the middle of a multi-week initial sync on a
+# rotating disk. There is nothing a 5-minute poll reports that a daily one does
+# not, and every failing poll was another Signal message - 83 of them in six
+# hours while the explorer was wedged.
+#
+# This is safe to scope to the host because monerod-box runs ONLY Monero units.
+# Do not copy it to a box with a mixed workload: the timer is one per host and
+# iterates every unit in monitored_services, so slowing it slows all of them.
+#
+# 26h, not 24h: the window must EXCEED the push interval, or a check reporting
+# exactly on schedule races its own deadline and alerts on jitter alone. The
+# 900s randomized delay puts the real worst case at ~24h15m.
+#
+# Host liveness and disk are deliberately NOT slowed - they answer "is the box
+# alive", which is still wanted within minutes. See infra/400.
+service_health_on_calendar: "*-*-* 05:15:00"
+service_health_randomized_delay: "900"
+service_health_heartbeat: "26h"
diff --git a/ansible/infra/401_service_monitoring.yml b/ansible/infra/401_service_monitoring.yml
index ab564a1..94828eb 100644
--- a/ansible/infra/401_service_monitoring.yml
+++ b/ansible/infra/401_service_monitoring.yml
@@ -64,7 +64,7 @@
           'name': (item.0.host | lower | regex_replace('[/_.,# +&]', '-')) ~ '/' ~ item.1,
           'group': 'services',
           'token': gatus_push_tokens[item.0.host],
-          'heartbeat': '11m'}] }}"
+          'heartbeat': hostvars[item.0.host].service_health_heartbeat | default('11m')}] }}"
       loop: "{{ host_units | subelements('units') }}"
 
     - name: Register the service endpoints
@@ -98,7 +98,16 @@
         healthcheck_check: systemd-units
         healthcheck_units: "{{ monitored_services }}"
         healthcheck_units_key_prefix: "services_{{ host_key }}"
+        # Cadence and heartbeat window are ONE decision, and both are a property
+        # of the host - monerod-box runs a multi-week sync nobody needs polled
+        # every five minutes, so it declares a daily schedule in its host_vars
+        # and a matching window above. Everything else keeps 5min/11m.
+        #
+        # An empty healthcheck_on_calendar means "use healthcheck_interval" -
+        # see the timer template in roles/healthcheck.
         healthcheck_interval: "5min"
+        healthcheck_on_calendar: "{{ service_health_on_calendar | default('') }}"
+        healthcheck_randomized_delay: "{{ service_health_randomized_delay | default('30') }}"
         healthcheck_boot_delay: "2min"
         # The per-unit results go to keys under this collection; the role's own
         # single-result push is unused here, so only the base is set.
diff --git a/ansible/infra/402_public_monitoring.yml b/ansible/infra/402_public_monitoring.yml
index c24df46..821ead5 100644
--- a/ansible/infra/402_public_monitoring.yml
+++ b/ansible/infra/402_public_monitoring.yml
@@ -31,8 +31,11 @@
       - {sub: "{{ subdomains.memos }}",              host: vipy}
       - {sub: "{{ subdomains.mempool }}",            host: vipy}
       - {sub: "{{ subdomains.datum_gateway }}",      host: vipy}
-      - {sub: "{{ subdomains.monero }}",             host: vipy}
-      - {sub: "{{ subdomains.monero_explorer }}",    host: vipy}
+      # Daily rather than the 6h default - see the Monero note under
+      # public_sites. A record that has not moved in a year does not need
+      # four looks a day while the node behind it is mid-sync.
+      - {sub: "{{ subdomains.monero }}",             host: vipy, interval: '24h'}
+      - {sub: "{{ subdomains.monero_explorer }}",    host: vipy, interval: '24h'}
 
     # A public resolver on purpose: this must test what the internet sees, not
     # what a local cache or the tailnet's MagicDNS happens to answer.
@@ -55,8 +58,16 @@
       # 401 is CORRECT: monerod answers an unauthenticated request with an HTTP
       # Digest challenge. Asserting 200 here would go green precisely when
       # rpc-login broke and the node started serving the world for free.
-      - {name: monero,      sub: "{{ subdomains.monero }}",             path: "/get_info", status: 401}
-      - {name: exmrplore,   sub: "{{ subdomains.monero_explorer }}",    path: "/",       status: 200}
+      #
+      # Both Monero sites are polled ONCE A DAY, not every 5 minutes. The node
+      # is a multi-week initial sync on a rotating disk and the explorer reads
+      # the same LMDB, so a hard poll measures the disk more than the service -
+      # and a wedged explorer turned that cadence into 83 Signal messages in
+      # six hours. `threshold` drops with it: 3 failures at 5m is 15 minutes of
+      # tolerance, but at 24h it would be THREE DAYS before anyone heard. A
+      # daily check has no room for a blip, so it alerts on the first one.
+      - {name: monero,      sub: "{{ subdomains.monero }}",             path: "/get_info", status: 401, interval: '24h', threshold: 1}
+      - {name: exmrplore,   sub: "{{ subdomains.monero_explorer }}",    path: "/",       status: 200, interval: '24h', threshold: 1}
 
     # Ports published from the edge host by socket_proxy.
     public_tcp:
@@ -99,7 +110,7 @@
           'name': item.sub ~ '.' ~ root_domain,
           'group': 'dns',
           'url': dns_resolver,
-          'interval': '6h',
+          'interval': item.interval | default('6h'),
           'dns': {'query-type': 'A', 'query-name': item.sub ~ '.' ~ root_domain},
           'conditions': ['[DNS_RCODE] == NOERROR',
                          '[BODY] == ' ~ hostvars[item.host].ansible_host],
@@ -118,10 +129,10 @@
           'name': item.name,
           'group': 'public',
           'url': 'https://' ~ item.sub ~ '.' ~ root_domain ~ item.path,
-          'interval': '5m',
+          'interval': item.interval | default('5m'),
           'conditions': ['[STATUS] == ' ~ item.status,
                          '[CERTIFICATE_EXPIRATION] > 168h'],
-          'alerts': [{'type': 'signal', 'failure-threshold': 3,
+          'alerts': [{'type': 'signal', 'failure-threshold': item.threshold | default(3),
                       'success-threshold': 2, 'send-on-resolved': true,
                       'minimum-reminder-interval': '6h'}]}] }}"
       loop: "{{ public_sites }}"
diff --git a/ansible/infra/403_service_probe_registration.yml b/ansible/infra/403_service_probe_registration.yml
index f6e6bf4..802df49 100644
--- a/ansible/infra/403_service_probe_registration.yml
+++ b/ansible/infra/403_service_probe_registration.yml
@@ -45,8 +45,15 @@
       - {name: mempool-mariadb,  host: mempool_box_local}
       - {name: mempool-backend,  host: mempool_box_local}
       - {name: mempool-frontend, host: mempool_box_local}
-      - {name: monerod,          host: monerod_box_local}
-      - {name: xmrblocks,        host: monerod_box_local}
+      # The two Monero probes push ONCE A DAY, not every 5 minutes, so they
+      # need a window wider than a day. 26h, not 24h: the window must exceed
+      # the push interval or a check that reports exactly on time races its own
+      # deadline and alerts on jitter. The timers are OnCalendar 05:00 and
+      # 05:30 with RandomizedDelaySec=900, so the true worst case is ~24h15m.
+      # Cadence lives in roles/{monero,xmrblocks}/defaults/main.yml; the two
+      # are one decision and must move together.
+      - {name: monerod,          host: monerod_box_local, heartbeat: '26h'}
+      - {name: xmrblocks,        host: monerod_box_local, heartbeat: '26h'}
 
   tasks:
     - name: Build the probe endpoint list
@@ -55,7 +62,7 @@
           'name': item.name,
           'group': 'probe',
           'token': gatus_push_tokens[item.host],
-          'heartbeat': '11m'}] }}"
+          'heartbeat': item.heartbeat | default('11m')}] }}"
       loop: "{{ probes }}"
 
     - name: Register the probe endpoints
diff --git a/ansible/roles/monero/defaults/main.yml b/ansible/roles/monero/defaults/main.yml
index 633f3c0..3d925ed 100644
--- a/ansible/roles/monero/defaults/main.yml
+++ b/ansible/roles/monero/defaults/main.yml
@@ -94,3 +94,16 @@ healthcheck_push_url: ""
 # Bearer token for the Gatus external endpoint. Required whenever a push URL
 # is set: Gatus rejects an unauthenticated push with 401.
 healthcheck_push_token: ""
+
+# WHEN TO CHECK. Daily, at a fixed hour, rather than an OnUnitActiveSec
+# interval that drifts with every restart.
+#
+# Prefixed because the generic `healthcheck` role owns the unprefixed
+# healthcheck_on_calendar; an unprefixed default here would shadow it for any
+# play that includes both.
+#
+# Paired with the 26h Gatus heartbeat in
+# infra/403_service_probe_registration.yml. Change one and you must change the
+# other: the window has to stay above the interval or the check alerts on its
+# own jitter.
+monero_healthcheck_on_calendar: "*-*-* 05:00:00"
diff --git a/ansible/roles/monero/templates/healthcheck.timer.j2 b/ansible/roles/monero/templates/healthcheck.timer.j2
index 8c850a9..c088af5 100644
--- a/ansible/roles/monero/templates/healthcheck.timer.j2
+++ b/ansible/roles/monero/templates/healthcheck.timer.j2
@@ -8,7 +8,17 @@ Description=Monero Node Health Check Timer
 
 [Timer]
 OnBootSec=2min
-OnUnitActiveSec=5min
+# ONCE A DAY, not every 5 minutes.
+#
+# A 5-minute poll of monerod buys nothing a daily one does not: the node is a
+# multi-week initial sync on a rotating disk, and every failing poll is another
+# Signal message. The cadence and the Gatus heartbeat window are ONE decision -
+# the window MUST exceed this interval, and it is set to 26h in
+# infra/403_service_probe_registration.yml. A 24h push under a 24h window races
+# itself and alerts on jitter alone.
+OnCalendar={{ monero_healthcheck_on_calendar }}
+# Spread against the other daily pushes leaving this box.
+RandomizedDelaySec=900
 Persistent=true
 
 [Install]
diff --git a/ansible/roles/xmrblocks/defaults/main.yml b/ansible/roles/xmrblocks/defaults/main.yml
index d90cab8..8254393 100644
--- a/ansible/roles/xmrblocks/defaults/main.yml
+++ b/ansible/roles/xmrblocks/defaults/main.yml
@@ -73,3 +73,9 @@ healthcheck_push_url: ""
 # Bearer token for the Gatus external endpoint. Required whenever a push URL
 # is set: Gatus rejects an unauthenticated push with 401.
 healthcheck_push_token: ""
+
+# WHEN TO CHECK. Daily, 30 minutes after monerod's own check so the two do not
+# contend for the same cold LMDB pages. See roles/monero/defaults for why the
+# name is prefixed and why this is paired with the 26h heartbeat in
+# infra/403_service_probe_registration.yml.
+xmrblocks_healthcheck_on_calendar: "*-*-* 05:30:00"
diff --git a/ansible/roles/xmrblocks/templates/healthcheck.timer.j2 b/ansible/roles/xmrblocks/templates/healthcheck.timer.j2
index 48713a4..6edf61d 100644
--- a/ansible/roles/xmrblocks/templates/healthcheck.timer.j2
+++ b/ansible/roles/xmrblocks/templates/healthcheck.timer.j2
@@ -7,7 +7,14 @@ Description=Onion Monero Blockchain Explorer Health Check Timer
 
 [Timer]
 OnBootSec=2min
-OnUnitActiveSec=5min
+# ONCE A DAY, not every 5 minutes. See the note in roles/monero's timer: the
+# explorer follows the node it reads from, and this check costs a full page
+# render out of the LMDB (a cold one measured 68 seconds), so polling it hard
+# is not free either. The Gatus heartbeat window is 26h, set in
+# infra/403_service_probe_registration.yml, and MUST stay above this interval.
+OnCalendar={{ xmrblocks_healthcheck_on_calendar }}
+# Spread against the other daily pushes leaving this box.
+RandomizedDelaySec=900
 Persistent=true
 
 [Install]