Yamaha carts, for example, have a standard four-year warranty and the batteries on electric carts have a five-year warranty. It is, therefore, reasonable to expect a minimum life expectancy of 4-5 years.  As with any product, it will come down to personal usage. A cart used for only one round per week is likely to have a much longer lifespan than a car used 5-10 times per week. Weather conditions will also doubtless take their toll. A cart is liable to last longer in a dry desert climate compared with the UK for example. The final variable is the level of care and maintenance. If the car is personally owned and well maintained it is likely to have a longer lifespan than one that gets abused by users and receives no regular maintenance checks.