What's your go-to for cache invalidation?

hey folks, im trying to nail down a consistent strategy for cache invalidation across our services. were using redis for a lot of our caching, esp for user-specific data. the write-through and cache-aside patterns are fine for writes, but keeping the cache fresh when underlying data changes outside of our direct control is tricky. what techniques or tools do you find most effective for dealing with cache invalidation, esp in a microservices environment? looking for practical advice, not just theory