Addressing the earlier point about drilling locks which can be picked, I worked as a Locksmith for 10 years, and I have drilled a lot of locks, which I hated, but which was often the only way to open the lock without very expensive specialist tools, or a massive investment of time in developing skill with less expensive tools.
I opted to teach myself to pick cylinder locks, including Mul-T-Lock and Banhams, as I hated drilling locks unnecessarily, and I could easily make the tools required myself. I started learning how to pick lever locks, and made myself a reasonable serviceable lever pick, but left the trade before I got anywhere near proficient. My employer at the time had less than zero interest in teaching me either, so it was all five in my own time and at my own expense.
When I was working I was pretty good
picker, and practised a lot - probably a couple of hours everyday, and on a wide variety of locks, and I was still regularly defeated by locks in the field. Even though I still practice occasionally in an effort to keep my hand in, my abilities have declined hugely. Maintaining a skillset which allows you to consistently pick everything you come across is a huge task, and simply not a practical reality for most lockies.
Specialist warrant locksmiths invest in tools and skills to open as non-destructively as possible, but the converse is that their lock fitting is often pretty rough.
When i drilled locks I did my level best to ensure I kept damage to the bare minimum, and this is a skill in itself - you should see what some "locksmiths" do to get a lock open - a photo from the 'black museum' is enclosed for you enjoyment.
