diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index e245c72959..019ee581c5 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -2095,6 +2095,7 @@ static void __sip_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod)
 				if (sipdebug && option_debug > 3)
 					ast_log(LOG_DEBUG, "** SIP TIMER: Cancelling retransmit of packet (reply received) Retransid #%d\n", cur->retransid);
 				ast_sched_del(sched, cur->retransid);
+				cur->retransid = -1;
 			}
 			UNLINK(cur, p->packets, prev);
 			free(cur);
@@ -2139,8 +2140,8 @@ static int __sip_semi_ack(struct sip_pvt *p, int seqno, int resp, int sipmethod)
 				if (option_debug > 3 && sipdebug)
 					ast_log(LOG_DEBUG, "*** SIP TIMER: Cancelling retransmission #%d - %s (got response)\n", cur->retransid, sip_methods[sipmethod].text);
 				ast_sched_del(sched, cur->retransid);
+				cur->retransid = -1;
 			}
-			cur->retransid = -1;
 			res = 0;
 			break;
 		}
@@ -2458,6 +2459,7 @@ static void sip_destroy_peer(struct sip_peer *peer)
 	}
 	if (peer->expire > -1)
 		ast_sched_del(sched, peer->expire);
+
 	if (peer->pokeexpire > -1)
 		ast_sched_del(sched, peer->pokeexpire);
 	register_peer_exten(peer, FALSE);
@@ -7818,8 +7820,10 @@ static enum parse_register_result parse_register_contact(struct sip_pvt *pvt, st
 	else
 		peer->username[0] = '\0';
 
-	if (peer->expire > -1)
+	if (peer->expire > -1) {
 		ast_sched_del(sched, peer->expire);
+		peer->expire = -1;
+	}
 	if (expiry > max_expiry)
 		expiry = max_expiry;
 	if (expiry < min_expiry)
@@ -12003,6 +12007,7 @@ static int handle_response_register(struct sip_pvt *p, int resp, char *rest, str
 		if (global_regattempts_max)
 			p->registry->regattempts = global_regattempts_max+1;
 		ast_sched_del(sched, r->timeout);
+		r->timeout = -1;
 		ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);	
 		break;
 	case 404:	/* Not found */
@@ -12012,6 +12017,7 @@ static int handle_response_register(struct sip_pvt *p, int resp, char *rest, str
 		ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);	
 		r->call = NULL;
 		ast_sched_del(sched, r->timeout);
+		r->timeout = -1;
 		break;
 	case 407:	/* Proxy auth */
 		if (p->authtries == MAX_AUTHTRIES || do_register_auth(p, req, resp)) {
@@ -12045,6 +12051,7 @@ static int handle_response_register(struct sip_pvt *p, int resp, char *rest, str
 		ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);	
 		r->call = NULL;
 		ast_sched_del(sched, r->timeout);
+		r->timeout = -1;
 		break;
 	case 200:	/* 200 OK */
 		if (!r) {