I've read that steel lockbar inserts dramatically increase the life of a lockface, yet I've also read that manufacturers use replaceable inserts so they can be swapped out when they 'wear down'. These two points seem kind of contradictory considering the relatively short time that inserts have become popular. I have personally never worn out a lock face, regardless of whether it has an insert or not, but I'm curious whether anyone else has ever had to replace a steel insert. Is it common for a steel insert to wear down to the point that lock rock becomes an issue? Will this be a common issue down the road for knives with inserts, or are they expected to perform for a lifetime?