Huh. I just look at my shoes and say, “the soles are peeling off.” Then I replace them. Similar with my bike. “I’ve had this bike for 35 years. Time for a new one.” I don’t know what would happen if I depended on Garmin to instruct me. Does anybody use this feature to schedule a shower?
Well, it doesn't instruct as max distance is entered by an user. Don't know from where you can take reliable distances for new models as manufacturers don't provide them. Someone would need to test a chosen shoes first, without that you can only enter common average value for sport shoes, so it's pointless.
But feature to track distance for a gear is useful, with it you can easier compare which shoes lasted for you longer.
Max distance could be useful if it would propose an average value from mileage of other users for a given model of shoes.