diff --git a/bin/tests/system/kasp/tests.sh b/bin/tests/system/kasp/tests.sh
index e0ea8d951a..dbeabcf381 100644
--- a/bin/tests/system/kasp/tests.sh
+++ b/bin/tests/system/kasp/tests.sh
@@ -2153,9 +2153,6 @@ active=$(key_get KEY1 ACTIVE)
 set_addkeytime "KEY1" "RETIRED" "${active}" 15552000
 retired=$(key_get KEY1 RETIRED)
 rndc_rollover "$SERVER" "$DIR" $(key_get KEY1 ID) "${retired}" "$ZONE"
-# Rollover starts in six months, but lifetime is set to six months plus
-# prepublication duration = 15552000 + 7500 = 15559500 seconds.
-set_keylifetime "KEY1" "15559500"
 set_addkeytime "KEY1" "RETIRED" "${active}" 15559500
 retired=$(key_get KEY1 RETIRED)
 # Retire interval of this policy is 26h (93600 seconds).
@@ -2171,9 +2168,6 @@ dnssec_verify
 # Schedule KSK rollover now.
 set_policy "manual-rollover" "3" "3600"
 set_keystate "KEY1" "GOAL" "hidden"
-# This key was activated one day ago, so lifetime is set to 1d plus
-# prepublication duration (7500 seconds) = 93900 seconds.
-set_keylifetime "KEY1" "93900"
 created=$(key_get KEY1 CREATED)
 set_keytime "KEY1" "RETIRED" "${created}"
 rndc_rollover "$SERVER" "$DIR" $(key_get KEY1 ID) "${created}" "$ZONE"
@@ -2198,9 +2192,6 @@ dnssec_verify
 # Schedule ZSK rollover now.
 set_policy "manual-rollover" "4" "3600"
 set_keystate "KEY2" "GOAL" "hidden"
-# This key was activated one day ago, so lifetime is set to 1d plus
-# prepublication duration (7500 seconds) = 93900 seconds.
-set_keylifetime "KEY2" "93900"
 created=$(key_get KEY2 CREATED)
 set_keytime "KEY2" "RETIRED" "${created}"
 rndc_rollover "$SERVER" "$DIR" $(key_get KEY2 ID) "${created}" "$ZONE"
@@ -3655,9 +3646,6 @@ check_apex
 check_subdomain
 dnssec_verify
 # Roll over KEY2.
-# Set expected key lifetime, which is DNSKEY TTL plus the zone propagation delay,
-# plus the publish-safety: 7200s + 1h + 1d = 97200 seconds.
-set_keylifetime "KEY2" "97200"
 created=$(key_get KEY2 CREATED)
 rndc_rollover "$SERVER" "$DIR" $(key_get KEY2 ID) "${created}" "$ZONE"
 # Update expected number of keys and key states.
diff --git a/lib/dns/keymgr.c b/lib/dns/keymgr.c
index 8d2f54eac8..4fbebbcb6d 100644
--- a/lib/dns/keymgr.c
+++ b/lib/dns/keymgr.c
@@ -2477,8 +2477,6 @@ rollover_status(dns_dnsseckey_t *dkey, dns_kasp_t *kasp, isc_stdtime_t now,
 		}
 	} else {
 		isc_stdtime_t retire_time = 0;
-		uint32_t lifetime = 0;
-		(void)dst_key_getnum(key, DST_NUM_LIFETIME, &lifetime);
 		ret = dst_key_gettime(key, retire, &retire_time);
 		if (ret == ISC_R_SUCCESS) {
 			if (now < retire_time) {
@@ -2487,7 +2485,9 @@ rollover_status(dns_dnsseckey_t *dkey, dns_kasp_t *kasp, isc_stdtime_t now,
 							  "  Next rollover "
 							  "scheduled on ");
 					retire_time = keymgr_prepublication_time(
-						dkey, kasp, lifetime, now);
+						dkey, kasp,
+						(retire_time - active_time),
+						now);
 				} else {
 					isc_buffer_printf(
 						buf, "  Key will retire on ");
@@ -2665,7 +2665,6 @@ dns_keymgr_rollover(dns_kasp_t *kasp, dns_dnsseckeylist_t *keyring,
 	retire = when + prepub;
 
 	dst_key_settime(key->key, DST_TIME_INACTIVE, retire);
-	dst_key_setnum(key->key, DST_NUM_LIFETIME, (retire - active));
 
 	/* Store key state and update hints. */
 	isc_dir_init(&dir);