About every 200 hours take your nozzle off. Do a nozzle check. If you do not have a nozzle gauge you can use a drill bit in the field to run the same test. If the test says you have a #5 nozzle (5/16th). That means a 5/16th drill bit should fit through it. A 3/8ths drill bit should not. By 16ths increments you can use a drill bit to determine if your nozzle is worn out.
