Whoa, that's a hard one to answer. ALL depends on your drive time and how large of accounts you have. I personally know of 1 company that runs 3 man crews all day. Told me that they had 180 accounts a week with that 3 man crew. I've personally have done 33 accounts in a 10 hour day with myself and another very experienced and driven individual, including drive time. Of course, these are 3000-5000 sq foot sub lots tight together. If you have larger accounts, that number will be much less. The amount is not what's important, it's the profitability of the crew. Remember with a crew, your paying for quicker times on your accounts. That's at least one reason behind it.
cwb20, your question was pretty vague. Size of the lawn means everything.
Some days I can only do three, but they are huge lawns.
Nobody would do this if we didn't make decent money at it.
Bastalker was a bit hard on you with his response, but its common sense. I mow part time along with a 40hr per week job. I only do 12 lawns currently, but I will be picking up 6 more this summer. It's like a hobby for me because I like gardening and being out-doors. Something I can't have in my current office job.
Like I said, it's a hobby but make no mistake about it, come August and that thermometer hits the upper 90's... lawn mowing becomes work and by November I am ready for winter and the grass to go dormant. If it wasn't for the money, I would dump my lawns in a heartbeat!
Yes, money is what its all about in this business... hobby or not.