I was a painting contractor for many years and never asked for a deposit upfront. A good contractor should have great credit with his suppliers and an even better contract if the deal should go south before the job is done. Get to know your customer and explain how each paint covers so they understand fully before you have to apply 3 or 4 coats. If you didn't bid your job right and the client has already signed the contract then that is on you not the client. Yes I haven had to eat the difference but the client was happy and a return customer for years so I made up for it.
Ask companies to include all details in writing. Although that sounds simple enough, too many contractors submit offers such as "paint house for $5,000." A friendly contractor may offer a reassuring handshake and promise that the crew will take care of all the details — starting on time, working every day, cleaning up, etc. That's great, but why not include each point in the proposal? If it's a challenge to get a written description of labor, materials and other details, things will probably get worse when the work starts.
These are some fantastic questions to ask and I particularly like the one that is concerned about safety for the painters. After all, if you have a large home and you’re hiring them to paint the exterior of that home then they’ll likely be on scaffolding. Because of that, you need to make sure that the contractor not only provides appropriate safety training, but has the correct liability insurance as well.