When I'm deploying database changes to an Enterprise system, I'll use snapshots to make rollbacks very fast and easy should something go wrong during the deployments. I won't keep those snapshots for any length of time once we've validated that the deployment was successful.
As for cleaning them up on a schedule, it really depends on why they're being created. What makes you think it's something you need to do on a scheduled basis?
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- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning