I mow about 4 acres with an Ariens Zoom 1640. Around the house is normal grass. Out back is about an acre of oat grass the previous owner planted to feed his horse. Oat grass grows pretty fast and is very broad leafed. I set my deck height to it's highest setting, but in the spring, the grass grows fast enough that I'm still taking maybe 75% off the top. It puts quite a load on the mower deck/belt. So, on to the topic. Last week I was mowing the back field and sure enough, the belt broke. I had replaced it last year when I was scalping an area of heavy weeds. (My bad) I was pretty bummed that my new belt didn't last until I started thinking about it. I knew the grass was too tall. And even though the grass looked dry, I did notice where I was cutting was damp. The engine would load up, so I would slow down (creeping speed.) But I also noticed the deck would stutter and it would leave rows of standing grass behind me. (belts slipping.) Then finally, pop! Quiet... (The mower deck is louder that the engine.)
So I got a new belt and put it on. (Man, that tensioner spring is hardy!) Then I cleaned the deck and sharpened the blades (Doh!) No more stuttering. No more corn rows left behind.
Mower deck maintenance is a bit of a pain, and I wasn't keeping up with it. I tried using a jack and jack stands, but I really don't get enough height. What I've found works pretty good is putting the ramps onto the back of my pickup and driving the mower up untill it's at a pretty good angle/height. (Back wheels still on the ground) My ramps have a strap that secure to the bumper to keep them from slipping, but it's still a little ify crawling under there. But the access is pretty good. Now I clean the deck more often (still not after every mowing..) and I touch up the blade edges with a hand file more often too. I expect this will extend the life of not only my belts but probably the engine and hydros as well.