I have done hundreds of brake jobs. What you should learn from the previous is- if you are able to safely turn your drums, do it. If your drums are out of spec and you need to replace them- turn the new ones also. The quality of all of our parts is getting worse and worse. You should be concerned about two things here. That the drum is round, most are not, leading to poor braking. The other thing is the condition of the mating surface, breaking the glaze, making the surface more consistent and allowing the shoe to "bite". There are times during a build that you can go "cheap", but doing brakes is not one of them. Do it once - do it right.