Hoists are designed for min 20 yrs operation considering that hoist will work 250 days per year for class 1, 300 days per yr for class 2 and 333 days per yr for class 3 & class 4.
Also per day working is defined in IS3938 table 1. Which states for class 2 will run 1.5 hrs per day. Class 3 will work 3 hrs per day and class 4 will work over 6 hrs per day.
Total working hrs of a hoist based on class is also defined in IS3938.