When working with GeoWebCache tiles, there are three main operations associated with any task: seeding, reseeding, and truncating.
The seeding operation will generate any tiles not already saved in the cache. If tiles are already in the cache, these will be preserved. This operation is best for typical usage on a static cache.
The reseeding operation will regenerate all tiles, even if already saved in the cache. This operation is used when data and tiles have become stale and need to be updated.