So how bad are the meters in this game? Like how many times an in-game hour do you need to eat to not starve and can you use your weapons for more than two kills before they break?
Eating and drinking isn't too bad - it's not so often it's annoying, and it's really easy to find tons of food and drink as you explore. It won't take long to build up a more-than-sufficient stockpile back at your base, which you'll have almost no danger of running out of.
By the time you're sleepy you're usually full of gear and ready to head back to base anyway - but there are generally beds liberally located on most levels so you can usually find a place to nap while exploring.
Weapons on the other hand seem to break down ridiculously fast (though you get way more than two kills!), to the point that you'll likely bring multiple weapons of the same type with you so you can switch them out. Luckily, upgrades don't wear out so you can just swap them over to the replacement weapon - though this makes it more tedious to swap to a less-worn-out weapon in hostile territory.
Luckily you can repair weapons for free (i.e. no resource cost), but only back at base, it doesn't take too long (can always sleep or craft etc in the meantime), but it only repairs up to 50% initially from memory (though the machine that does this can be upgraded so it's faster and repairs more).
Weapon also use ammo is in the form of energy (which is also used for your torch and "shield" when activated). Carrying a number of these is usually a good idea, though I tend to actually have less spare energy cells than I do spare weaponry.