how do you handle cache invalidation

Hey folks, I've been thinking a lot about caching lately, especially how to keep data fresh without causing too much overhead. We're using Redis for our primary cache, and while it's great for speeding up reads, figuring out the right invalidation strategy is tricky. Do you primarily rely on Time-To-Live (TTL) based invalidation, or do you have more event-driven approaches? How do you handle complex dependencies where changing one piece of data requires invalidating multiple cached items? Curious to hear what works for you