Change History

If the cache/log still exist you can still find it and log it.
You are also allows to write i the log first when you are not qualified and qualify later so it is useful if you wrote i the log before.

There is not work in maintaing them. The scripts it likely still used on active caches and the config for a cache is just a shot text config. The database usage is small in comparison to other stored data.

I cant see a problem in keeping them

If the cache/log still exist you can still find it and log it.
You are also allows to write i the log first when you are not qualified and qualify later so it is useful if you wrote i the log before.