I wouldn't paint.....how many rooms? say-living room and 2 bedrooms maybe a dining area? I'd get some area rugs from a carpet warehouse-they'll cut any size and bind them off and put a felt like backing.....even when you proceed to refinish you might like the area rugs. Is a little perimeter of the wood showing going to be a big issue?-usually that looks good with area rugs.We did this with some bedrooms that become other purposed, and I don't think painting the floor would be good at all...some of the scrappy looking finish on the wood shows around the edges of the room-it's not an eyesore. I guess people have different tolerance for imperfect, but I wouldn't paint a hardwood floor unless it was an old porch or butler's pantry-some little niche like that and it's part of a theme showing someone's "done up" creativity.

I second the rug idea, doesn't have to be anything expensive.

This would require a lot of rugs (the rooms are huge). Also, I worry that rugs would just hold moisture there--if there are spills or the dog pees or whatever.

The dining area and kitchen are taken care of--we used that "grip strip" flooring from Home Depot. It's all vinyl. The issue is basically hallways/bedrooms/living room.

you'll have money if you are getting rent/correct? landlords also collect damage deposits...so there is a pool of money for you...refinishing floors isn't rocket science and the "products"-polyurethanes-are quite good-coats can be done within 24 hours to build up a finish. what exactly are you anticipating from this dog? I moved into a house where the owner had a St Bernard and there wasn't a "ripped "up or" dinged" up anything, and there is a lot of wood here. I polyurethaned an old heart pine kitchen floor with 3-4 coats of Benj Moore water base satin in a weekend.....this is a lake house with boots in winter and flip flops with sand in the summer, and the finish has held up.

Old house with original floors redone. It has been 7 years with a 70# dog and no signs of anything other than normal wear (which has been minimal) even if it didn't include a dog. The main issue is how well your renter will treat the home and clean/maintain as needed. Placement or moving a piece of furniture will do more damage if not done correctly.

You're setting yourself up for disappointment here. It's unrealistic to attempt to "protect" wood floors with paint. That will cause more issues if you ever go to refinish them than you would be "saving" by doing that. Putting down a cheap carpet over them would come the nearest to doing what you want. Even then, it won't be as cheap as you probably envision.

I know you don't want to hear this, but you can't have your cake and eat it too when it comes to a rental. You have to mentally disassociate yourself from any emotional attachment that you have for the place, and treat it as the disposable property that tenants will. If you can resign yourself to completely replacing the flooring in the home whenever it's status changes, you'd be better off. You're not going to "save" those floors from people treating them like crap, no matter if they are friends or not. Renting to friends very often leads to the dissolution of that friendship. I wouldn't do it. Find another renter. One without pets.

Check at a paints store - you may be able to put a coat of shellac over your floors for a quick fix.

I would refinish with a protective coating on top but not paint to ruin good floors. Be able to kiss the place goodbye at the outset or don't rent, but prepare and hope for the best. I would put rugs down with one of those moisture barrier type pads underneath made for pets. Have only heard of them.

Have a healthy security deposit in place to cover damages; put it all in writing. Agree renting to a friend you value is not the best of ideas. You never know what might happen.