So, how do you handle cache invalidation?

were implementing a new feature that really relies on caching to keep response times snappy. The main challenge now is figuring out the best way to invalidate that cache when underlying data changes. We've considered TTL-based expiration, but that feels too coarse. Anyone have experience with other strategies, like write-through, write-behind, or event-driven invalidation? What are the trade-offs youve seen in practice?