As teenagers, my best friend and a fellow shade tree mechanic once told me. Jokingly: "If you finish a major rebuild and find an extra bolt, just put it in the oil filler hole on the valve cover. It'll find its way into the right place"! LOL
He was infamous for stripping bolts or breaking the heads off of them. I told him to figure out what 'snug' means, depending on the part. We used torque wrenches too, but only for things like clutch pressure plates, axle pinion nuts and head bolts. Most everything else was either: barely snug, snug, real snug, or F'n tight. Depending on the parts construction of aluminum or steel, and if the bolts held the engine or axles on.
LOL
I've found many 'free' nuts and bolts after working on stuff. Usually found out where it was supposed to go because something was rattling.
I have always made it a habit to keep the bolts and nuts with the removed part.