Depending on the symptoms of your problem, your troubleshooting actions will be different.
For example, if you see nothing in the access logs of the consumers, a network problem may be the cause of the replication failure. Reinitialization is not required.
If the error log shows that it cannot find a particular entry in the change log, the master's change log is not up-to-date. You may or may not need to reinitialize your topology, depending upon whether you can locate an up-to-date change log somewhere in your replication topology (for example, on a hub or other master).
If the consumer has problems, for example experiences processing loops or aborts locks, look in the access log for a large number of retries for a particular CSN. Run the replck tool to locate the CSN at the root of the replication halt and to repair this entry in the change log.