Michael! I love that I’ve caught your eye!
I’m not sure about lifespan yet. I only started developing the shoes in May, and have been wear-testing models since September. But 3 months in is way too early to come to any lifespan conclusions. It’s fun wearing your own product daily though. And so far, no problems.
My gut feeling is that a pair will last at least 6 months for someone with a normal gait. If worn by someone who drags their heels, things might be a little different, I think they could wear a hole in them in about that time. The current out/midsole is a little over 2mm thick, but the TPE has good abrasion resistance.
Also, the TPE can be recycled into ‘new’ filament pretty well. So old shoes can be shredded and used to print new shoes. I’m real excited about that, but will first have to sell quite a few more shoes.