Three mechanics, one socket set, no lost 10mm

A family friend, a mechanic, bought this socket set in 1964 and used it until he died in 1986. The current owner's dad took it over and used it until he retired, then handed it on in 2014 when the owner opened a garage. It's stamped Chrome Vanadium, made in Hungary. It has been leaned on against rusted old bolts and hasn't broken a corner. Every piece gets cleaned and oiled regularly and goes back in its slot at the end of each day, finished job or not. Nothing has gone missing on this owner's watch, not even the 10mm.