I buy ~$25 training tires (currently liking the Forte AMR+) and ride them until the rear tire is looking very square. This takes about 4k miles. Then I replace both tires because I'm vain and want matching tires. Also $50 is not a lot for 4k miles, I can afford it.

I bought a set of Conti GP4000s a few years ago. I couldn't detect a significant handling difference and I had two ride ending cuts within 3k miles. I promptly went back to the cheaper/tougher tires.