save wood floor on our first flip?

[Dana Novakovich]

I am a new investor and working on my first flip. 1st day of demo and we found old wood floors throughout 80% of the house. living room, dining room and hallway each have about a 3' x 3' cut out of the wood that was replaced with sub flooring. We did budget for all new flooring in the house. My question is do I tear up the old wood floor and try to salvage and sell?, Do I just lay new flooring over everything and move on or do I try to keep what I can of the old wood floors even though they may not match? My inclination is just to go over all the old flooring but I don't want to make a rookie mistake! What do I do??