Since I moved into an apartment with a coin-op washer and dryer, I do laundry much less frequently because it’s, quite frankly, annoying and expensive. This, however, necessitates me keeping a close eye on my underwear drawer. I learned the hard way that inevitably, you will run out of your cute underwear at the exact moment you need it most, forcing you to dig to the back of your closet to unearth the pair of old panties you’ve had for years. Like, not even tier three underwear—we’re talking the stretched out beige ones that have at least one hole. Such are the rules of the universe. Cue Psycho music.

This begs the question: When should you throw out your underwear? Aside from being aesthetically unappealing, is it unhygienic to wear decades-old underwear? (Ew, that sentence just gave me chill in a bad way). “In terms of safety, you’re not likely to die if you wore the same pair until they fell apart,” says Felice Gersh, MD, and author of PCOS SOS: A Gynecologist’s Lifeline To Naturally Restore Your Rhythms, Hormones and Happiness.

But in terms of when to overhaul your underwear drawer, common sense rules apply: If it smells, has lost elasticity, or has holes are all pretty solid indicators that you should toss them, according to Alyssa Dweck, MD, and assistant clinical professor in the Department of Obstetrics, Gynecology and Reproductive Science at the Mount Sinai School of Medicine.

But you don’t have to wait until your intimates are in a state that you’d be embarrassed to be seen in them. Aim to strike a balance between sustainability and self-care by following Dr. Gersh’s general guidelines: “When they start to look ragged, that’s when you should get rid of them. You’re worth the investment—go get new underwear.” Doctor’s orders.

Ready to refresh your underwear drawer? Here’s a guide to the nine pairs every woman should own.