When should i change my tires?

I bought my 3 years ago(camry 2005), and I bring my car to the dealer to rotate the wheels 1 time but i had never changed the tires. My question is how can i check the condition of the tires to see whether should i go buy new tires or not. Where can i get the good deal on the tires and what brand that you guy reconmend?? Thankssss When should i change my tires?
Pinch a Lincoln-head penny, from the base, between your thumb and forefinger, so that the top of Lincoln's head and the words ';In God We Trust'; are showing.



Place the top of Lincoln's head into one of the tire tread grooves -- try to measure in the lowest point within the tread.



If any part of Lincoln's head is obscured by the tread, you're all set -- you have a legal and safe amount of tread. However, if you can see above Lincoln's head or any of the ';In God We Trust'; letters above his head, then you are ready for a new tire.



I got a pretty good deal from firestone they sold me 4 tires for my big conversion van for just $175.oo was a sale in there weekly flyerWhen should i change my tires?
Every new tire sold today has wear bars running side to side across the tire, when they are exposed you need to replace the tires. As to where and what tires to buy, I like tirerack.com they have great tech articles and tire reviews as well as recommended tires for your car
My dad's a mechanic and he always taught me to use a penny. Hold it so Lincoln's hair/head is in the tread of the tire. If you can see the top of his head/hair, you need to replace your tires. Keeping your tires properly inflated makes your tires last longer, too! I hope I helped!