The finish on a piano has no effect on the sound it emits, but like driving a clean car makes a more careful and cheerful driver, it does feel better if the finish is beautiful. In the world of furniture refinishing, there are “regular” finishes, and “piano” finishes. The difference is vast. Veneers used on piano cases are hardwoods, some with particularly large pores. A piano finish is a closed-pore finish. The result is a perfectly smooth finish, either satin or polished, but always without the small but very visible cavities where the cell structure of the wood causes unevenness through the pores. Arriving at such a finish is very time consuming and requires a great deal of lubrication in the form of elbow grease, but the results are worth the effort.
Fully half the cost of a fine grand piano is in the finish. The same is true in restoration. Action parts are not cheap, pin blocks require time to fit properly, but all is overshadowed by the cost of a good refinishing job.
Years ago I subcontracted refinishing. I paid thousands of dollars and was consistently disappointed in the results. I finally decided I could do better myself and though sometimes I am still frustrated, I am usually pleased with the results.
I have found a refinisher whose work I like, but he is located in Baltimore and is very expensive. I use him occasionally, but mostly I do my own refinishing.