[stomachmonkey]

It's generally a good idea unless you want a flat in your Tahoe that's loaded to the hilt at 80 MPH then a couple of months later you get another flat with you/wife/kids/inlaws in the vehicle at which time you realize the tire shop did not replace them last time and 3 of them are dry rotted so after putting your 1 spare tire on you decide to go straight to a tire shop, any tire shop you can find but only make it another mile or so before a 3rd valve lets go completely stranding you cause now you have no spare and roadside won't come out if you don't have one causing you to call a cab to get the family home while you wait for a friend to come get you and one tire so you can find a shop to fix it then go back and swap it out and drive like a madman back to the shop to get the 3rd and final one taken care of.

Ask me how I know.