

I’m a locksmith so any time since the invention of the pin tumbler lock 150ish years ago I will be fine. I don’t prefer it but I can hand file keys without any electric key cutting machines. Before that the bit and barrel locks that were used I know enough to get by though admittedly I don’t know enough history to say roughly how long ago those were invented.
Locksmith here, my most used and most important tool is a pen because if you can’t write up the invoice you don’t make any money.