How many years will a bulldozer last?
Those large bulldozers used at mines sometimes work as much as 20 hours a day, nonstop, carving the ground and building the roads for large dump trucks to drive on. It is common to replace those bulldozers after 4 or 5 years, as they are worked very hard and intensively.
Small and mid size bulldozers that you see around in the cities and residential areas last much longer compared to large bulldozers as they tend to work more intermittently. Some of them last 20 years or more with proper maintenance.