About how many miles can you put on tires before they need replacing?

Mine are not cheap tires, but middle of the road. I bought them in May of 2005 and I put about 25,000 miles on them. It is hard for me to tell by just looking at them, and I do not trust a tires salesman!|||Next time you are in a tire shop have the salesman show you the wear bars which are molded in the tread of every tire, when the tire tread is worn to the level of these wear bars its time to replace the tires. The wear bars run across the tread at several points along the circumference of the tire, so you can see one no matter how the tire is turned.|||if they are rotated and inflated properly and your driving habbits are not bad like spinning and breaking hard and cornering like nascar you can get about 10,000 miles more then the tire is warranted for. but that doesnt mean you wont have premature tire failure it even happens to brand new tires .|||depends on driving habits , breaking habits and road conditions.|||Depends on a lot of things. Some obvious ones are:how often you use the car, the car size and where it's used to drive.|||Check tire for tread depth 3/32 in min. and dry rotting