One thing we have found most helpful is to use a tire store that puts a warranty on the life of the tire. Then, if they don't last and have to be replaced for pretty much any reason surprisingly, they credit you for the amount of time that should have still been left on the life of the old tire and the new tire is not quite as expensive. Has saved us loads of money over the years. The chain we use is Discount Tires. I think other chains like NTB have similar warranties.