Someone I know was venting this weekend about the real estate agent who listed her house taking Sundays off. I was appalled at the seemingly automatic expectation that the agent should be at her beck and call, no matter what she wanted or when. (All she wanted was an update on her house's listing... and it had only just been listed this week.)
I felt a little defensive for the real estate agent's sake, and I realized it was because I've encountered that attitude in clients myself: the notion that just because they hired me to do a certain job, it means that they own all of my time. One client, for instance, wanted me to be on chat all day long, so that I was at his beck and call any time he wanted. And he was paying me for a fairly small contract, not anything close to a full-time job.
A contract is not slavery. It does not give you the right to make unlimited demands on my time.
So let's talk about what you can expect from a contract.
You have the right to expect that I'll get the work done on time. If I choose to work on a night or a weekend to get it done, that's my choice, but definitely not your right to expect it.
You have the right to expect that my work will be professional quality. For a writer, this means that my copy will be well-written and error free. For a real estate agent, the expectations would be slightly different, but still -- working on Sunday is not necessarily a requirement for professionalism.
You have the right to expect that I'll follow all instructions and contract terms.
And that's about it. See, the reason people like me take contract jobs is because we like the freedom to get the work done on our own time, free from the politics of working in an office and having our time micromanaged. If you want someone you can require to work weekends, hire an employee.
If, however, you want to free yourself from the financial obligations of an employee, and pay for just the work you want done, hire a contractor. If you want to just assign the work and have it appear in your inbox when you need it, no babysitting or hand-holding required, hire a contractor.