They can provide a modern and fresh look to your units, attracting potential tenants.Fresh coat of paint: Hiring a painter to give the units a fresh coat of paint is an excellent idea.

The walls and ceiling have to be washed first, then multiple coats of Kilz, then paint.

We have in our lease that, at move-out, tenants are required to clean the carpets as part of returning the unit to move-in condition, and, depending on the type of carpet, applying a stain resistance coating such as scotch guard.

As others said if the cupboards are in good shape, a coat of paint and new hardware can do wonders, just make sure you use paint that works on cupboards.

@Jordan Coates "Keep buying and selling" that's the plan, buying more real estate and selling more insurance ;^).

If you are going from a darker to lighter color, it may take a second or third coat in the areas that there is writing. 

I spent the first hour after I got the keys sitting on the staircase starring at the coat closet because I had no idea what to do first.

You will need new flooring, paint, carpets, drapes, etc...and a complete new paint job with multiple coats of primer and high quality (read expensive) paint.

If you have a full coat of paint though, that can easily be close to 1k.

The way market is I'm not going to sugar coat, it's very hard to find a good properties for buyers.