How to resurface a hardwood floor?

it might just need a buff to remove the finish before adding a new one. It’s a beast of a job if you don’t have the equipment or know how to do it. I’d start with some you tube DIY videos and see if you want to go there in the first place.

The best thing for hardwood floors is bare feet. The oils from your feet condition the wood. The oil closest to what a human produces is jojoba oil and I use it to condition the wood in my house. It works wonderfully!! I didn't need a bit of revarnishing. Maybe try a small spot and see if it works for you? It's really not that expensive and you can add essential oils to freshen the home also. Sometimes I add lemon to help clean the staircase handrail. I buy the golden jojoba oil through bulkapothecary.com for the wood and the clear for my hair :) I looked up the prices, took a snapshot of the page, cropped it, and labeled it for you so you could see. I hope it helps you. Their essential oils are good. Personally I wouldn't get oils from anywhere that that the USA nooked long ago. What's in the soil doesn't just leave. So I get my oils through young living that my dogs will come into contact with or I use only the organic from bulkapotherapy.com

Wow! I'm rambling on with my information like I'm about to write an article. I'm sorry 🙄

Is it missing in some areas? Has the wood changed color in those areas?

If so, you’ll need to lightly sand the finish in order for the new polyurethane to stick. It’s also going to have to be wiped down with alcohol to get rid of any residues.

If you hire a pro, you’ll have a warranty.

If the finish is chipping or worn down in some areas, but not others, I would definitely sand it all down to keep it all cohesive. If it's all the same without chipping or damage, I'm sure you could do more of a light sanding to give the old finish more grip, and then revarnish it.

I would for sure sand it first. Then apply finish, lightly sand, apply second and third coat that way.