I'm with Vaz. Had a truck tire delaminate once, plenty of tread but 12 yrs old. 80 mph with a loaded gooseneck one dual let loose, that was enough for me. I will admit it showed dry rot and cracking but since then nothing over 7 yrs old on my autos. 5 yrs on a bike. I also admit I'm extremely anal about tires, we never wear them to the wear bars before replacing. I've zipped too many bags over people from neglected maintenance, my kids laugh at me checking their tires shocks, tie rods, etc.