One of the biggest problems with non-custom themes is that when a new update for the theme comes out (ie – pre to post sidebar widgets), you have to re-do all of the CSS code modifications that you changed before.
Or, if you’re lazy like me, you might even just say screw it and use the defaults from then on, if you even chose to upgrade in the first place.
Not any more.
I just stumbled across this: (Yes, I know it’s a year old, but I just found it today, so here you go!) How To Protect CSS Mods For Any WordPress Theme
Nothing groundbreaking, but it’s a simple, yet effective, way to customize a distributed theme to your liking, and not have to worry about your mods when the author makes any changes.