You can use one floss pick for several days. If you're using a brand that is biodegradable or compostable (like these), then it's even better if you can reuse them as many times as possible. That said, some people like to use a new floss pick every time they floss. There's no wrong way to do this! If you want to switch out your picks every day, that's okay too—just make sure not to leave your used ones on the sink or countertop where they could make their way into the trash bin and end up in landfills.