Have to jump in here

I have included quite a lot of hacks from vb.org in my forum last week (first time hacker), and I am rather frustrated that there is
another vBulletin update so soon after 2.2.4.
My question now is: how do you guys do an upgrade? Do you compare the new files with your hacked ones? How do you identify new code? How do you tell the difference between you hacked code and newly inserted one from the update?
Thanks for a basic explanation