As a freelancer I have some jobs that are like that, fixed cost and my problem how long it takes me, but most clients prefer if I'm onsite and that means I get

As a freelancer I have some jobs that are like that, fixed cost and my problem how long it takes me, but most clients prefer if I'm onsite and that means I get paid to spend 8 hours a days in their office. I have the exact same problem, I spend half the time looking busy. Or I could go home and only get half the money.