Tennis Racket - 4 to 6 years
Signs It's Time to Toss The frame is bent; the grip is worn-out or feels slippery.
How to Make It Last Longer "Replace your strings frequently because they bear the brunt of a racket's wear," says Chris Lewis, creator of tennis-experts.com.
Tennis Balls - 4 to 6 hours of play
Signs It's Time to Toss The ball is waterlogged (from being left out in the rain) or has bald patches on its surface. It doesn't bounce as high when you hit it.
How to Make It Last Longer Store balls in their can, away from extreme heat or cold.
Bike - Frame, 20 to 25 years; gears and chain, 5 to 10 years
Signs It's Time to Toss There are dents in the frame or rust and kinks in the chain.
How to Make It Last Longer Store your bike inside; take it to a bike shop once a year for a tune-up; keep the chain lubricated and replace it every 1,000 miles.
Bike Tires - 2 to 3 years
Signs It's Time to Toss The rubber is flaky or you feel the wheels slipping on the ground when you brake.
How to Make It Last Longer Never ride on underinflated tires; check the pressure before every ride, and watch for debris along the road to avoid flats.
Bike Saddle - 3 to 5 years
Signs It's Time to Toss The seat looks deflated and feels uncomfortable; the leather is torn beyond repair.
How to Make It Last Longer Wipe down the surface with a damp cloth and mild soap after every ride; patch tears immediately.
Bike Helmet - 3 to 5 years, or one major crash
Signs It's Time to Toss "Replace it if you've had a crash or if it has frayed straps or the protective foam is crumbling," says John Linn, a product expert for REI.
How to Make It Last Longer Don't throw it around— small dents and dings can lead to cracks.
Kayak - If you care for it well, it may outlast you.
Signs It's Time to Toss There are cracks or dents in the hull of the boat.
How to Make It Last Longer Rinse the interior and exterior with fresh water after every use. Don't drag the boat along the ground. Use the handles to carry it.
PFD (personal flotation device) - 3 to 5 years
Signs It's Time to Toss The foam feels hard or doesn't "give" when you squeeze it; the straps are torn.
How to Make It Last Longer Rinse with fresh water after each use and dry it in the shade. Don't hike through bushes wearing it or it could tear.