And what parts should I keep on hand? Anything known to be high failure? Firing pin, bolt?
I've seen reports of strikers cracking. It would be good to have a couple extra of those. Same for the firing pin.
I've had two bolts -- in two separate rifles -- have the narrower front lug shear off. Each was after about 2,000 round counts (my rounds), but the true count is unknowable as these are military surplus parts. Mine were in VZ2008's, but after this happened the first time I scoured the Internet and found three other such occurrences: Two were from Canadian versions and one from a Czech point (I believe that post is still on this forum). It could have been misalignment in my two separate rifles, or it could have been metal fatigue from substantial use and abuse in military service and automatic fire.
So... getting at least one extra bolt is probably a good idea. If you do, check the headspace. If you're lucky, it should be a straight swap. If you're not so lucky, you've got three factors that affect headspace: The carrier, the bolt, and the locking piece. The locking piece has the most effect. The problem is that it's impossible to determine how each individual locking piece will affect headspace. The stamped and scribed numbers have no consistency, making it impossible to "order" the correct one. Pretty much keep buying them until one makes everything fit.
If you're going to be taking yours apart at all, it's a good idea to have a collection of the tiny springs and plungers. Numrich's is a good source:
https://www.gunpartscorp.com/search#query=vz%2058&page=1So is Clearview Investments:
https://www.clearviewinvest.com/vz58.aspxThere are a few other places. Ebay from time-to-time has a lot of spare parts, but that seems to have dried up recently.