Unclear on when to revert, when not to, etc.

[aharown07]

Hi... new to vBulletin. A guy's been helping me w/a development site and we've customized a few templates a bit and I've adjusted all the colors and a few of the graphics.
When I upgraded from 3.7.2 to 3.7.3 pl1, there was (for a while) some stuff in admincp about reverting. Had to do some other things and now it's not there anymore.

In any case, I'm unclear on several things regarding upgrading and reverting and such.

First, if I revert and don't like the results can I "unrevert"? That is, will the cusomizations we've made still be around somewhere in some form so we can put them in again or whatever has to be done?

Second, my impression after a good bit of reading is that reverting becomes necessary under the following conditions: templates have been customized in some way + upgrade includes new versions of those templates + vB therefore doesn't upgrade those particular templates because it would wreck the customizations. So you have to find a way to get the latest templates applied and get your customizations moved to it... am I right so far?

So how does "reverting" help with that? Sounds like it would have the same result as if the upgrade script just went ahead and applied the new templates in the first place. So I must be missing something.

I hope the good folks at vB.com have long term plans to make that whole business less messy. (-: I should probably mention that I've installed the mod TMS (I think... it seems to be installed), but I haven't a clue how it makes any difference.