Do safeties and triggers wear out?

[soccerref]

I have a remington 742 in .30-06. I got this gun as a college graduation present in 1986, I bought it used at the time.

Question is, do the parts inside it wear out? Is there something in there that could need replacing to explain the following:

- When loading we put a bullet in the chamber and drop the bolt on it. When we pulled that bullet out at the end of the day, the primer had a small dent in it from what appears to be the firing pin. I've heard rumors of these guns doing this and firing upon chambering the next round.

- can something wear out so the safety "jumps off" by itself? My son had the gun and twice found the safety off, once while he was sitting.

- Can the trigger mechanism, or part of it, wear out to allow it to be fired while the safety is on?

Gun has me nervous now.

[soccerref]

Well the gun is getting one last chance this weekend, except in my hands, not my sons. Can't believe I'm doing this, but he gets my new rifle for the day Sunday (he can't hunt Saturday).

If anything funny happens with me and that rifle, which has been good to me for 22 years, well off it goes.