How long should I keep the tires on my car if I just had them mounted and they were manufactured in March 2013? They have good tread, almost new. I got them from a guy selling four of the old 5-spoke rims ($1000), which is why I bought them as Tesla doesn't make them anymore so I wanted spares. They came with tires on them. Two of the tires look brand new - one manufactured 2015, one 2016. But two are older and were made in 2013, and have slightly less tread on them. They are Goodyear Eagle TS A2 model tires. He said they came on a CPO Model S he bought, and he got new tires/rims for his car. I found one car tire company site that said strictly based on age, tire life can be 6 - 10 years. What does the forum think?