No lawn mower is designed to cut wet grass. Wet grass clogs up your blades and bogs the machine down. That can result in damage to the spindles,etc. Always let the grass dry out first. Also,I'd tell the homeowner to let you cut it every 7 days,not 10. Thats just an extra three days for the grass to grow taller and thicker. On my large properties that I cut 1.5-5.6 acres,I will only cut them once a week except for in the fall. If they can't go for that,I tell them to look in the yellow pages. Cutting large properties puts alot of wear and tear on a mower,so try to cut them before the grass gets too tall.. Keep the strain on the mower down.