changes (as above), it's fair to assume an average of 365 pairs tied per year – that's a total saving of 730 seconds = 12 minutes per year.
assuming that one learns to tie shoes at the age of five, and assuming that one lives to the ripe old age of 85 – that's a total saving of 58,400 seconds = 16 hours per lifetime.
of course, those 58,400 individual seconds can never be combined into one continuous usable chunk of 16 hours. but considering that most people think of shoe tying as a chore, it's pretty cool to spend that much less time doing that particular chore over the course of 