It would almost be easier for me to list the ones that have broken then put a lifespan to them.
Ever since I have moved to optical USB mice, of the dozens that I have used at home or work, only 3 no longer work. Ironically 2 of those were "high end" mice. The budget Microsoft and Logitech mice seem to last forever. I only just replaced the original Microsoft optical wheel mouse my grandmother had after ~10 years of use after a button broke. My other ones of that era are still going fine.