I won't presume to know enough about your specific situation to give you specific advice. What I will offer is other scenarios. Choose the one that makes sense to you.
A floor sweeper, as you have mentioned, charges by the hour. He automatically limits the amount he can earn by the number of hours he has to work.
An IT guy working for a company is usually on salary, where it doesn't matter how long or hard he works. He always gets paid the same.
A plumber usually charges by the hour, "plus parts and other expenses". In order to make his money, he might do the diagnosing of the problem or job himself, then hire others to do the "grunt work" while he goes out to find more work.
A construction contractor usually charges by the job. He creates a bid, then if he wins the bidding, makes the necessary arrangements to acquire materials and perform the work. In many cases it's flat-rate, with provisos for unusual situations such as acts-of-God, etc. He makes his money by bringing the job in ahead of schedule, or by saving money on materials or hiring less expensive labor to do the work.
An IT consulting firm usually has people who FIND the work, people who DO the work, and people who KEEP TRACK of the work. Usually there are way more people to actually DO work, but while they are doing their job, someone is out finding MORE work. That way there's always money coming in from somewhere.
When a lawyer charges, he either charges by the hour, by the service or he charges a "retainer" to make himself available to provide service as needed. Each of these methods has its own place; that is why a lawyer uses all three in different cases.
As you can see, each of these scenarios is quite different. So the question is, which one fits your situation best?
Good luck to you!
