My lawn was showing a rough choppy cut until I bought one of these.
Makes it easy to adjust the deck to the perfect height. Side to side and front to rear.
Find a level place to park the mower...slide this under the deck to the blade end and adjust. (I think it was about $15)
I scrape the deck underneath almost every mowing. To make it easier, I use a mo-jack to lift the front of the tractor.