I used to hire contractors for a business. In your “unsure” list- they had uniforms but they weren’t required (of anyone). Both employees and contractors needed to dress professionally for the jobs and most did prefer the uniforms rather than worry about their own clothes. We also did provide for and pay for a cell phone for one of our contractors who did not have one (and could not get one, LONG story). It was issued in the company name and in his contract that it is property of the company and used to contact him about jobs; although as the person paying the bill I can tell you he used it more than that but I was willing to look the other way on it. It was a flip phone without a data plan or anything. My contractors also drive company vehicles.

We did not guarantee a minimum per week; they were paid weekly by the job rather than an hourly rate or salary. Didn’t have the availability issue per se but my hours were roughly 7am-6pm weekdays so the only times they get calls are during those times. If I had a lot of unresponsiveness and had someone else to call I would have. I tended to more often deal with having to beat off walk-ins looking for work with a broomstick. We rarely had people stop wanting work.

One other thing regarding the vehicles- make sure you discuss contractors driving them with whoever insures you. I was told that generally speaking anyone I give permission to is covered while they were driving, but in practice they like to run a driving check on everyone, require that they have had a license for a certain number of years, etc if I am adding people by name to the policy. You should also look into how Workmen’s Comp would handle you using contractors and if that might affect your rates at all.