Are you contemplating doing the work or hiring it done?

DIY stair tread repair and finishing is not difficult nor expensive. A random orbit sander, a hand sanding block, sand paper---180 grit for the ROS and 220 for the hand block----dust mask, good paint brush with man made bristles($15), can of paint thinner, quart of oil based stain(color of the floor), rags(for applying stain), and a half gallon of Sherwin Williams varnish are all you need. Total cost is less than $100

Sand to bare wood with the ROS. Sand out the scratches but you do not need to get off all the old stain, just all the old finish. Apply stain with a rag, wiping it on a tread. Wipe the stain off as soon as you finish the tread and check color. Too light---reapply and leave it longer before wiping off. Too dark----wipe with a rag dampened with thinner.

Let the stain dry for 24 hours. Sand lightly with the hand sanding block. Wipe off all the surfaces with thinner to get all the dust/stuff off the wood.

Apply varnish. The secret is to cover with as thin a caot as possible---that eliminates runs. Use a flashlight/small lamp to shine from one end of the tread/riser as you look fron the other end. You can see the coverage that way---and any missed spots.

Let the finish dry 24 hours, resand with the hand sanding block just to scuff and recoat. Three coate will be sufficient.

To rerpair any marks after that, sand and feather in varnish.

I have just sanded 3 of my stair treads with a 50 grid sandpaper using a block electric sander, I thought I was suppose to sand down to the bear wood, now after reading your comment, can I now begin to just take of the old shine or do I have to continue to go to the bear wood, will the stain appear different? I have oak treads

msdeb