I recently picked up a nail on a rear tire. Acura patched it from the inside (I don't drive aggressively nor track the car ) and I drove it a good 50 miles monitoring that tire. This morning that tire was flat again. I am going to have Discount Tire take another look at it. If it continues to slowly leak I will likely replace that tire. Since the NC1 has 4 wheel drive everybody seems to recommend replacing all 4 tires at once. The rest of my P-Zero's still have 6/32nds of depth remaining. Since I drive only about 3k miles a year, likely would last another couple of years. I aim to replace with all seasons with the next set. Tire Rack offers a service to shave a tire to match the remaining 3 on the car. This seems like a decent solution rather than throwing away 3 perfectly good tires. Thoughts? TIA