Wow... 6 quarts?!? For decades, the standard engine on all commercial 60" zero-turns was the Kawasaki 25 hp V-twin, and that takes something like 1.6 or 1.8 quarts, depending on specific configuration. My $15 comment was based on that, and honestly probably a little dated for inflation, but I don't really think the cost matters much against the cost of the machine.
I love the suspension. I negotiated my then-nearly-new Deere ZTrak in with the purchase of my house, the prior owner had bought it just two years prior, and didn't really need it where he was going. It's a great mower, but would not have been my first choice, since the Deere ZTraks are well-known for being way stiffer than nearly any other commercial zero-turn. It mows great, but literally beats the hell out of me.
I just pulled up the maintenance spreadsheet I keep on all my OPE, and see I marked the greasing interval as "50 hours or yearly, whichever comes first". So, I guess I should also be doing a mid-season greasing. I probably do only 75 hours of actual mowing per year, but put more hours on the engine and hydro by using that machine to tow walnut harvesters around the yard for a few weeks each fall.
My oil change interval also has an "or yearly" clause, meaning it should never be left more than a year, no matter what the hours are. Again, manufacturer recommendation, YMMV.
