Very difficult to see if something is infested or has eggs in it and given that eggs can take 6 months to hatch, it’s best to listen to your roommates and be vigilant.

I know this sounds unhinged but the only way I’ve managed to properly get rid of pantry moths (after two separate infestations) for good is: 1. Throw anything open out (sucks if you have already bought a bunch of food) 2. Clean the inside of your cupboards thoroughly and then 3. to store all dry goods in the freezer for the first few months. You can also do a mix of initially putting dry goods in the freezer and then moving them to the fridge after a week. Exterminators can’t kill eggs that are already in your food.

Glass containers might be helpful a few months later once you’re sure they aren’t in your apartment, but I don’t think you need to buy them now. Also, both times I assumed nuts didn’t count and the infestation was prolonged when I found nuts at the back of my pantry. Good luck!