Some of us do other things than build furniture from new lumber. I for instance have planned several thousand liner feet of oak flooring and several thousand feet of long leaf pine flooring. I have hit many small tacks. I have a helix cutter in my planner and the carbide bits are cheep and easy to rotate or replace. I visually look for the small nails but cant find them all. Lots of paint over them and such. No way I could ever afford to buy #1 log leaf pine, even if I could find it. All this "used" lumber is coming out of my 1914 house restoration and being put back in looking brand new.