Comment by sanity

It depends on the nature of the data, for example in our group chat app River[1] it stores the most recent messages - deleting the oldest to make room for the newest as necessary. Banning a user will remove them from the members list along with their messages, and recently banned users are stored in a banned list (like a tombstone).

So there is no one approach to this, rather you design the approach based on the application, and since contracts are just webassembly they are extremely flexible.

[1] https://github.com/freenet/river