Stop/start system long-term wear?

Re the most engine wear occurring in the first few minutes of driving. I reminisce about the 1970s and even -80s when the rule of thumb was to warm an engine up before driving. In those days the starting systems themselves were a major wear and tear item with many a ring gear failing. Do you have any data on the wear and tear incurred by the stop-start systems of today? Surely they are going to give trouble in years to come and I usually switch mine off when I start the car.