I bought it for like $40 or less for a 5 gallon pail of JD303 equivalent oil at gri supply. All you do is pull the drain plug, pull the cover that holds the screen in, pull the screen out, blast with compressed air, soak in deisel and then spray if really dirty or you can use like brake clean on it. Reassemble and fill. Literally takes longer to pour fluid in than all the other stuff once you have done it more than once. But even first time its as simple as i say.
And yes if you dont know when the last time you changed it was i would change it. Many do it here once a year. I think hydro fluid is like 500 hours but if most of us waited that long it would take 20 years to change it. I personally do mine about every 2 years, not that i think its dirty or anything but its more likely it has some water in it by then that i want out. I keep it under a shed but when its out working at the farm and it rains its out in it, also there is condensation.
