i have used them when traveling or sometimes when i come back from traveling but not an every day thing. i can now tell when im in ketosis without them by the awful breath. anyway if you do buy them, buy the bayer brand, those from ebay dont seem to work as well. i check the date on them, and keep them sealed and out of the bathroom no moisture when i have used them. i buy 100 from the pharmacist for 18 dollars and have had them forever. just my opinion when they are any color from pale pink to dark purple i have successfully lost inches and pounds.