Using contractors that aren't bonded and insured puts you at risk if anything goes wrong with the job and in case the contractor doesn't fulfill his end of the bargain. Depending on where you live and what sort of work you're doing, you may need to make sure your contractor is licensed, too [source: Angie's List].
Bonding and insurance are two different things, but ideally you want a contractor who has both. Think of bonding as protection once the job is complete and insurance as protection while the work is going on [source: Angie's List]. When you choose a bonded contractor, you're protecting yourself in case he fails to pay subcontractors or just plain does a terrible job. If your contractor isn't bonded and flakes on something like this, you're the one who foots the bill. The contractor's insurance covers you for on-site problems, like an injured worker who otherwise might sue you for medical costs or damaged property that you'd have to replace out of your own pocket.
A good contractor will also be willing to work with you to stay within your budget by going over the proposal to see where you can cut back. One way that my family has saved money on construction projects in the past is by sourcing some of the materials ourselves, like light fixtures and bathroom cabinets, and even doing some of the smaller tasks, like hanging ceiling fans and installing doorknobs and bathroom hardware. Watch out when you're taking on parts of a construction project, though – you don't want to end up in over your head (which brings us to our next mistake)!