I have bought a number of tools in sets but more than 50% of sets are untouched. For example, I use five socket sizes (10mm, 12mm, 14mm, 17mm and 19mm) out of 12 available sockets (a set from 8mm to 19mm) in 3/8" drive. Wrench utilization is similar as I use four (8mm, 10mm, 14mm and 17mm)...