Sure:
I have a stack of individual locators that are maintained as their respective data changes. Within that stack are a couple that don't change (like freeways), but the others, streets, address points, common name points are always in a state of flux.
When you publish a composite, or any other service for that matter, you can do it one of two ways:
1. If you register the data the services use with the ArcGIS server, the published service is linked to the original data.
2. If you do not register the the data the services use with the ArcGIS server, all that data is packaged up and sent to the ArcGIS Server.
With the first option, in order to rebuild a locator, you must shut the service because there will be a lock on the locator. I chose to go with the second option as it allows me a bit more flexibility with my work flow. I don't want any connection with ArcGIS server and the original data sources. If the workspace where the original data sources reside has some sort of failure, I need my geocoding services to remain up and running. [I use the term workspace instead of hard drive or machine, as everything I do is in the virtual environment.]
I can update data, I can rebuild and test locators, I can add or delete locators from the composite; basically whatever I want, without impacting the services. When I'm happy with what I have, I simply publish the composite, and off it all goes, replacing the old with the new. With respect to your question, no I do not re-create the composite. There is no need. You can do this nightly. You can do this every two weeks; montly, yearly. You can do this as often as you like.
I hope this clarifies it for you.
That should just about do it....