A lead screw use a helix angle and a nut to convert rotary motion onto linear motion.
Life time and Maintenance
Life times are typically long and maintenance consist of lubricating.
For accurate life time estimations, a case study under controlled conditions similar to the use case is required. Theoretical estimates of life times are often based on specified recommended design load and typical operating speed. It is recommended to do these calculations if you'r lead screw are going to operate at 500 rpm or higher. In the case where the combination of loading, speed and duty cycle exceeds a certain limit, failure is predictable and will occur rapidly.
RepRap Example Speed Calculation
With a distance per revolution of 8 mm, 500 rpm translates to a linear operating speed of ca 66 mm/s, which for a RepRap 3D printer would be quite fast, but nothing unusual.