Cabinet doors A kitchen or bathroom cabinet door or two might be just what you need to add a little personality with open shelving.
Closet doors Awful mirrored sliding closet door or something else you just don't love? Take it down and add something you do, like a patterned fabric. Also great for tight spots where a door swing might get in the way of needed furniture.
Unneeded hardware like paper towel holders, etc. We've got this rusty, metal paper towel holder in our kitchen. We don't use paper towels. What's something you don't use that you could take down to improve the space?
Old blinds Is there anything worse than old, dirty, bent blinds or when a landlord's not down to replace them? Carefully take them down, fold them up and replace them with something else you love. Just consider what you're getting and whether it would be able to be used in a home with different-sized window openings if you plan on using your stuff again.
Handles and pulls Works best when you have new door pulls that have holes that match existing ones. Be careful not to damage the doors or drawer faces when taking off old pulls.
Old lighting fixtures Changes to globes and shades can often be done inexpensively, quickly and easily and sometimes even going bare bulb (if it fits your aesthetic) is better than something old-fashioned (in a bad way).
Remember to remove and take things down carefully. The goal isn't to break anything as you're taking it down, so if something feels stuck or delicate, leave it where it is. Just remember the aim is to be able to re-do everything you've undone, so be sure to put everything in one memorable spot. Place all hardware in plastic bags clearly labeled. Consider taking photos of the process of doing or undoing complicated hardware so you remember how to replace it.
Consider even using tape to number the hardware in any order it has to go in. Make sure you don't store these things in places that might get wet, dirty, or nibbled on by vermin, and take a peek at it every few months to make sure you remember where it is and that everything is okay (and it hasn't been buried by other things). And of course, even if these are temporary changes, you might want to ask your landlord for permission.
What temporary changes have you ever made to a rental that you put back once it was time to move out? Do you have any horror stories of trying to take something down and breaking it? Let us know!
(Images: Adrienne Breaux, and yes, I do need to take my own advice!)