I personally use a combination of loads and executions when it comes to packages,functions, and triggers. The thing you have to look out for is the size of your SP. Too big fragmentation... too small poor performance. So, what I do is normally any object with 100k + executions and 20 or more loads I pin. With cursors if they've been loaded once I pin them all. I also have a procedure that I use to pin all that good stuff into memory at start up.

With tables I check the top sessions and see which sql statements have been executed the most, along with the physical reads and see who my biggest problem children are then I cache those tables.