Here’s what I do now, and you can laugh at me: I write the opening date on every sanitizer bottle with a permanent marker. If it’s been more than two weeks since I started it, I use it only for cleaning surfaces, not my hands. For hand use, I refill a small travel bottle from a large, newly-opened container every Sunday.
Yes, it feels a bit neurotic. But honestly? During cold and flu season, and with all the “new normal” habits we’ve picked up, having trustworthy sanitizer is a tiny victory. And hey, if you see a cloudy pump at a café, don’t be shy—ask them when it was last changed. They’ll either respect your vigilance or think you're a weirdo. Either way, your hands win.
So, to answer the original question: every week for personal bottles, every two to three weeks for dispensers, and immediately if it looks or smells off. And please, for the love of clean hands, stop topping off old bottles with new solution. That’s like pouring fresh coffee into a moldy cup. Just no.
