Tried waiting three days for Chet to restock, but he never does?

Im sure they do, but more than three days

otherwise people would keep sleeping/waiting there till they have the items they want

Probably more than 3 days.

I have seen merchants restock, but none I frequent, only ones I go back to after a while. It might be tied to your level as it seems I see different stuff after leveling, but that could be more due to the time it took to level up rather than the level.

Also, the really good stuff, your not going to buy it, your going to find it.

Edit I don't know who Chet is, but do remember that some merchants will never carry the good stuff. Chet might be a low end merchant too.

I just wanted to find some of the Varmint rifle mods. Figures that when I don't want them, they're always there but when I want them, they aren't. :s

I can't remember the exact town I got most of those in, but it seems like Goodsprings and Primm were it for Varmit Gun Mods, and I did not find much elsewhere, mods or otherwise for those guns.

You could go to the broc flower cave instead, and get the Ratslayer. It's a unique Varmint Rifle, and the nice thing about it is it already has all the mods- extended mag, night scope, silencer.

http://fallout.wikia.com/wiki/Broc_Flower_Cave

Chet is the name of the shopkeeper of the Goodsprings General Store.

Then he should have the upgrades.

Wonder if they are leveled in some way. I only scoped the Varmit then after a couple of quests, and levels, I could get the silencer, but never saw the extended mag. And, the silencer may have been there early on but I put it on towards the end of the tutorial. I have not been back since. Might have to do that. I could use some low level enemies, it will be like a vacation.

takes a while to restock and if you sell stuff you might not notice it (keep track of the caps they have on hand if you sell enough for them to have 0 caps and now they have more then they restocked) seems gun runners restocks faster then others. They are only leveled by weapon not by mod type as that is random I found the varmit rifle stuff easier at the vendor in the dino in Novac then I did Chet in goodsprings.

Generally speaking - unless they've specifically mucked with the vendor's inventory in a non-standard script - all NPCs restock 72 hours after your last visit to their cell. Go somewhere else, save, wait 4 days, then go check. If it's no good, save-scum back to the previous save and wait 4 days again. Rinse-repeat until they stock what you want.

("Save scumming" is an old term from the Moria/Angband days. As you descended/ascended stairs, it would randomly generate the next dungeon level. Combine that with the "level feelings" which would tell you vaguely whether there was epic loot or named monsters on the new randomly generated level and a lot of players would save-scum until they got a good or exceptional feeling. Other players would frown on that tactic and call them scum for abusing the save/reload system that way. The term may even be older then that, going back to the days of Rogue/Hack.)

Early on, Chet sold the night scope for the varmint gun. But I was a fool and didn't pick it up right then, so now I'm forced to make the circuit of all the merchants that sell weapon mods every few days looking for one... curse you RNG, curse you to Death Valley.

3 days plus 1 hr