I just had my hardwood floors (most are oak with one room pine) refinished with 3 coats of moisture cure. They look great. Is there any benifit of putting on a 4 coat? Or, should I just leave it alone? I want it to last as long as possible.

Thanks.

Moisture cure urethane is extremely hard.3 coats is sufficient but you can do another if you want to.

I get asked that all the time. I tell my customers that it won't protect the floor any better than three coats. Save the money on that 4th coat, wait a year or two when it might start to get worn, and spend the money on a coat then.