Hello Marketing Cloud Trailblazer,
We have recently connected Salesforce CRM with Salesforce Marketing Cloud. We have set the polling schedule as 15 minutes and are able to get the objects in synchronized DE. However, we would like to know if there are any best practices we should be following, any recommendations that can be helpful in the long run, or any issues you might have faced that we can take care of now.
I appreciate your help in advance.
Lukas Lunow (NoA Ignite) 
Forum Ambassador
I think this is a really broad topic, but it can actually a really nice and informative thread, if more people will share their thoughts. Let me start with few obvious ones:
1: always use native CRM IDs from supported objects (leads, contacts, users) as Subscriber/Contact keys. By not doing this, you will miss out on a lot of OOTB features of the connector.
2: enabling record sync of leads, contacts and users automatically adds them to your billable contact count in SFMC. Hence it is seen as best practice to introduce a custom boolean field on these objects, indicating whether this record should be synced or not.
3: you don't need multi-org connector to sync your data to multiple BUs. This is done using automations and shared data extensions
4: become best friends with Journey Builder's Salesforce Data Event and Salesforce Campaign Event for easy triggering of journey entries in real time based on data changes in CRM (not to mention all the other cross cloud features of JB)
Next please :-)
