There aren't too many houses more difficult to list and show for sale than a rental house. Usually the tenants are still living there, which requires that Agents schedule appointment times with them rather than being able to drop by whenever works for their buying client. Sometimes the tenants are moving out, which may alleviate the appointment scheduling, but usually leaves a BIG mess in the house, as tenants are not usually as concerned with cleaning up after themselves, as they are just getting into their new place. Since renters are not as likely to take care of the property, most rentals I see are fixer-uppers in need of repair and landscaping work, as well as a heavy-duty clean-up crew. And sometimes, you get an even bigger surprise.
I was showing a client of mine some houses this past weekend, one of them being a rental. We arranged an appointment with the gal living there. Her roommates were moving out, so there were boxes and garbage throughout the whole house. We basically had to weave our way through their mess to get from room to room and some rooms we couldn't even see the floor for all the boxes and garbage. But our added bonus was their cats. Well, to put it more distinctly, their cats feces. Oh, the smell in the house was overwhelming! Obviously the cats had been peeing in the house for quite some time and the renters must have just been used to it. We took a look in a loft that was added onto the house and found that the cats had been using the space as their catbox! Ewwwww! It does make it a little difficult to envision all the wonderful uses of a loft space in a house, when it's covered in cat droppings that haven't been cleaned up in who knows how long!
My suggestion for sellers who are listing their rental house: Do NOT list your house for sale until your renters are moved out and you've had the entire house cleaned, as well as the yard landscaped. Yes, it means a little extra time and money, but it will be well worth it. You'll be able to ask a much higher price for a house that is ready to move in, than to deeply discount a trashed rental due to all the mess and smell and garbage left-over from the renters.