Caching Mental Model

Caches are like trash cans. When throwing out trash it goes in the closest bin. We don't walk to the trash can in the garage or outside everytime. We collect it in different sized bins around the house.

Read through caches are when the closest can is overflowing. It goes in the larger one in the kitchen.

Cache time to live (TTL) is trash days. The trash is "expired" and it has to leave.