I typically get around 400-600 kms out of a fresh pair of running shoes before the tread is completely gone and the energy return structure stops returning energy. I typically run about 100km/week. A bit less if I’m tapering, or injured (not very often), or on holiday. I also walk a lot, which I have different shoes for, but that adds an extra few pairs to the annual shoes bill as well.

Edit: I probably go through shoes slightly faster than most runners, because I weigh a bit more than most runners. But I don’t think that’s a huge factor.