Hello! /forums/images/graemlins/laugh.gif
Regular maintance usually consists of changing a hydraulic filter, topping off the hydraulic fluid level, and that's about it for the hydrostatic equipment that I own. It shouldn't leak. If it does, there is a problem.
As for how many hours before seals start to go, there are probably too many variables to figure that out. For instance, if you run in dirty conditions all the time, check the fluid levels without cleaning the cap first, never change the filters, let it over heat often and get dirt in your hydraulic quick connectors all the time, it probably won't last as long as somone that maintains their equipment as suggested by the manufacturer. /forums/images/graemlins/wink.gif
I'd check with some high hour owners of the units that you are considering and see what they have to say.