Veg-tan leather (what I use, tanned from vegetable-derived oils like from barks) is incredibly strong. You can't really mess it up unless you're trying to with a sharp thing. It can get scratched, sure, but this is pretty heavy leather (I think it's about 7-8 oz but I don't know for sure [in case you're not familiar, '7-8 oz' does not describe how heavy the sheath is, it's just a way to measure the thickness]). With lighter leather like 2-3 oz you run the risk of it getting torn from being over-stretched or broken from punctures and whatnot. Basically if a leather thing is made well, it's going to withstand pretty much anything it would encounter day-to-day. I guarantee you I can stab it as hard as I can with that dagger and it won't puncture.
As for the watch, thank you. It's a SEIKO, so it's certainly an upgrade from the $19.99 CASIO Forester I bought for myself from Walmart.