I used to feel the same way until about 2004. I had 6 tires that were about 8 years old and looked brand new. Had maybe 2000 miles on them. Took off on a trip and within 250 miles lost 3 of them. One blew the side wall off and 2 lost the tread. These were 10 ply Continental Tires made by Michelin. Now I was force to buy all new tires on the road. When the guy took the tires off the wheels to mount 4 new ones, I was going to keep the old ones as spares, I was amazed. They insides were breaking down and they had devolved bubbles in the rubber of which some had popped and allowed air to get between the plys.
Long story short I bought 5 tires so I had a good spare and keep the best looking old one as a secondary spare. A year later I was in my house and heard something that sounded like a shotgun go off in my pole barn. I went out and it had blown up and put a hole in the wall it was leaning up against. Good thing my daughter was not in there getting her bike or Barbie Jeep out. They were parked 3 feet from that TIME
BOMB!
Chris