Yeah, I lost one of the lower cowl screws during the first couple of weeks.
I plan to buy about 5 of each type body screw (with & without shoulder, 3 different plastic body nuts) just to have on hand.
If you want to get down & dirty, you will want a large torque wrench for checking engine mounts and axle nuts.
If you get a copy of any workshop manual, be aware that published torque figures are notorious for being wrong - even in factory manuals. Don't assume that just because you have a number and a nice new wrench that all is going to be fine. Common sense is your best tool.
Has there been any mention on this forum of engine mount fasteners coming loose? I have not read any, but I only see maybe 10% of the stuff on here.