Mine uses regular automatic transmission fluid and it should last forever without ever having to change it. Even if you use your lift twice a day everyday.
So at 2 mins X 2 X 365 days = 1460 mins a year. 1460/60 = 24.33 hours a year. (one day a year)
Even if you change your ATF every 50,000 miles in your car, it would take at least 50,000 mins to equal that time (833.33 hours)
833 / 24 = 34.71 years.
So if my math is correct, and you raise and lower your lift twice a day (lowering the lift doesn't really count if you ask me), then its still going to take nearly 35 years to get the equivalent usage out of the fluid as you would driving it 50K miles. And I don't know about you, but my lift only gets used on the weekends, if then. So in another 50 or so years, I wont be able to remember how to use the thing anyway.