The life span of a T-shirt is not as long as you wish it were. Once a tee goes through one, maybe two summers, it's ready for under-sweater-only status. Here's how to keep your tees white and shapely for now.

Most of the manufacturers of the T-shirts we tested recommend washing in cold water, but according to Jane Rising, a manager at the International Fabricare Institute, detergents function better at higher water temperatures. So if you dare challenge the label:

Wash in warm water; hot water can cause shrinkage. Use the permanent-press cycle for drying.

Use fabric softener to avoid wrinkles, and remove clothes as soon as the dryer shuts off.

To keep whites whiter, don't overload the washing machine. Put in only whites — no prints or pastels.

To help restore original whiteness, try a bluing agent, like Mrs. Stewart's Bluing, which counteracts yellowing ($12 for three bottles at www.mrsstewart.com).