Most lawns around Olympia, Lacey, and Tacoma are cool-season grasses like perennial ryegrass and fescue. They grow fastest in spring and fall and slow down in the dry heat of July and August, and your mowing schedule should follow that pattern.
From April through June, plan on weekly mowing. Grass can grow an inch or more a week during this stretch, and letting it go two weeks means cutting off too much at once, which stresses the lawn and leaves heavy clumps of clippings behind.
In mid-summer, if you're not watering much, growth slows and many lawns do fine every other week. Raise the mower a notch during this time. Taller grass shades its own roots, holds moisture better, and stays greener into August.
The simple rule is never to remove more than a third of the grass blade in a single mow. If your lawn is at four inches and you want it at three, that's one cut. If it's at six, it's two cuts spread over a week.
Sharp blades matter as much as timing. A dull blade tears the grass instead of cutting it, leaving brown, frayed tips and openings for disease. On a professional schedule, blades are sharpened often enough that you never see that ragged look.