So I have a bit of a quandary here that only happens to BITOG types who try to over optimize everything. On my 2003 Sable my rear tires are at 4/32 but the right rear inner measurement at the lowest point is 2/32. The front tires are at 7/32. The tires I want next are Potenza Serenity Plus. If I change all 4 this month I get a $70 rebate. Existing tires are Avid TRZ that should last 80000 miles. They start at 12/32 However, the rears have had 35k on them, the fronts have 16k on them. I am in CA so am thinking the rears will be ok during summer even though at one point one tire is very near or at 2/32. I calculate that the fronts still have 10k to 15k in them. The rears maybe 4k - 8k if that inner does not wear anymore. I had the shocks changed all round recently and am wondering if the inner wear was from before or is new (the left rear sits a little lower both before and after the shock change). The rears were rotated with each other 6k ago. I calculate that if I change now, I am going to spend $70 in wear on the new tires if they last the rated 75000 miles. If they last 55k then that's $100 and if they last 35k like the Avid TRZ then that's $150. All of these offset the current month $70 rebate. The pros of changing are having a 4 wheel set of matched tires which, according to tirerack ratings are going to be a big improvement over what I have now. If I wait then the fronts will be changed in 2 to 3 years time. What would you do? Options: 1) Change all 4 now and get the rebate 2) Buy all 4, change 2 now and change 2 in 2 to 3 years. Is storing for 2 to 3 years an issue? 3) See through summer and change only the rears when needed and then the fronts when needed in 2 to 3 years 4) See through summer and if another deal comes, then change all 4 at that time What's the likelihood of another rebate deal after summer is over?