changing hydraulic fluid

how often do you need to change the fluid out in the pumps? only reason i ask, is i have 2 drums of it, and i have nothing going on at work for the next couple of days, so i was gunna change it all out. is it needed?

I usually do it every 6 months or so...will probably help your seals last since we aren't running filters (which next setup I will be).

i do it everytime i changs orings,,,so yea bout every 6 months

how is the best way to do it? suck all the fluid out of the pumps, refill it, then raise and lower the car a few times. then suck it back out, refill it and repeat? or would it be better to fill the pumps up, take the wheels off, and disconnect all the fittings from the cylinders and just 'pump' the fluid through the lines into a bucket? then when it starts coming out clear, hook the lines back up? thanks.