While it's a great idea to wear gloves to keep fingernails protected when cleaning and doing yard work, is it true that keeping them covered in nail polish makes them weaker? Many women will keep nails bare for days or weeks between painting them, and some forego nail polish altogether because they believe nails need to "breathe." Although it isn't true that nails are breathing, it is possible to weaken nails by painting and removing polish without caring for nails in other ways.
Polish can keep nails stronger, but it also can discolor and dry out nails, and polish is often difficult to remove. If nails are strong and thick, polish may help keep them that way to some extent, but if they're already weak -- and bend and tear easily, or have peeling layers at the tips -- polish may help them grow out, but it also could make them weaker.
Nail-biters might find it helpful to use polish to keep themselves from chomping down, but those who like to peel can find it too tempting -- removing layers of nail polish along with layers of fingernail. And nail polish removers in particular cause drying and breakage for many, so depending on the health of your nails before you layer the red, black, pink or green, you may want to give 'em a break every now and then.