New tires YOKOHAMA AVID ASCEND . Loss about 1-2 mpg. Not upset.

30k miles on mine. They still look good and handle well. Discount Tire/America's Tire does my free rotation every 5k when I change the oil. They haven't suggested I'm anywhere close to wearing them out. I just recently started taking the Prius out on some dirt roads to get to some fishing spots. The tires have been fine on the dirt, too.

 

A tire tread depth gauge is handy item for the glove box. They’re a little more obscure than pressure gauges, but yeah: good twosome.

 

True. I've always just used a penny when in doubt but there's no doubt with these tires yet.

from How to Tell if You Need New Tires | Firestone Complete Auto Care

"


Place a penny head first into several tread grooves across the tire. If you always see the top of Lincoln's head, your treads are shallow and worn. If this is the case, your tires need to be replaced. If part of Lincoln's head is always covered by the tread, you have more than 2/32 of an inch of tread depth remaining."

 

A penny doesn’t cut it.