I use 12 pt. in hand sockets and 6 pt in impact sockets. Other than spark-plugs rarely have I ever needed a 6 pt with thin walls, but when that time comes, and I fully expect that it will, I'll buy one and then it lives for eternity with that vehicle and not in the general tool box. If it a really big fastener I'm not opposed to turning down the OD of an HF 6 pt impact socket. As it happens my 1-1/8" HF impact over the bottom .75" or so is about .09" smaller OD than it started life as.