1. You double-up when hanging them on hooks.Using hooks to hang-dry towels between uses isn't that bad (though using a towel bar is better), but you should never hang more than one per hook. Moisture and debris could get trapped among the layers, which growing bacteria and mold just love.
And your bathroom's hand towels should be changed and cleaned even more often. "They get dirtiest faster since you use them more than once per day," says Carolyn Forte, Director of the Cleaning Lab at the Good Housekeeping Institute. "Change them every couple days, or even every day, if you have a big family."
3. You use the same towels too often.A diligent laundry schedule doesn't mean you can get away with one towel per person. "It's good to have several sets, maybe four, that you rotate," says Forte. "This way, each set is only used about every other week. Less use and less washing means towels will last longer."
4. You use too much detergent when you wash them.It can be tempting to pour a little extra into the washer when you want to get something really, really clean. But this tactic is futile, as the package's recommendation is really all you need. Plus, as towels are meant to be absorbent, they tend to cling to excess suds. If not rinsed thoroughly, leftover detergent can actually feed bacteria and mold. "It can also leave towels stiff, rough, and scratchy," says Forte. If you notice residue or extra stiffness out of the wash, dial the detergent back.
5. You don't wash them in hot enough water.Check the care tag and wash towels in the hottest water safe for the fabric to really get them clean and kill germs.
(Tips from www.housebeautiful.com)