Agreeing to let someone repair or improve your home takes a giant leap of faith. After all, this is your home we're talking about. More than just a roof over your head, it's where you and your family spend a large part of your lives together, from first steps to first proms. Plus, your home is likely your most significant financial investment.

So, when you hire a contractor, you have to trust that he or she will not only do the job as agreed but also respect your home and its contents. And, when you hire the wrong contractor, it can be a real nightmare of broken promises, half-completed jobs, and eventually legal action.

With that in mind, let's consider some warning signs that let you know this contractor might best be avoided.

1. They work alone.

Okay, this isn't always a bad sign; many capable Chuck-in-a-truck handypersons and contractors are out there. But if it's a more significant job, it likely requires more than one person to complete it safely and efficiently. So, if the contractor in question says they're going it alone, it probably means they aren't financially solvent enough to pay additional workers-and that could mean serious trouble.

2. They won't give a written estimate.

This is a big one, especially if the bid is too good to be true compared with other contractors. This could indicate some bait-and-switch scheme, where halfway through the job, the contractor \"suddenly realizes\" that it's more complex than he or she initially thought and that it will require more materials and/or labor. At this point, they'll count on your not wanting them to leave a half-finished job to force you to pay the extra money. This situation can be avoided if you have the estimate in writing. And, if they won't provide a written estimate, you shouldn't agree to the job.

3. They're rude, unclean, or otherwise unpleasant.

This may seem like a minor thing, but it can indicate significant problems going forward. When someone doesn't care about their appearance or treat you rudely, it suggests that they don't respect themselves or their customers. This poor attitude can indicate a lack of pride in their work. This often predicts a negative experience for you, the homeowner. By the way, the appearance thing extends to the state of their vehicles and tools too.

4. They have lots of negative online reviews-and respond to them negatively.

Anyone can have a negative review or two. Usually, it's pretty easy to tell if it's the contractor's fault or if it's a case of a customer being unreasonable. But if the reviews are uniformly negative, this should be an obvious red flag. The other warning sign is how the contractor responds to negative reviews. If they do so aggressively and try to attack or discredit the reviewer, this could indicate the contractor really is at fault and is simply being defensive. On the other hand, if they offer to make it right, this could indicate one that will go out of their way to make sure the homeowner is satisfied. That's the mark of someone who wants to do a good job.

5. They ask for cash only.

This is a big red flashing warning sign. Cash is virtually untraceable, so it is a good indicator that the contractor doesn't want to report his or her income to the government-which means they're willing to break the law. It also offers the homeowner no protection should the job go wrong (unlike a check that can be canceled or a credit card transaction that can be disputed). And, as with the first point, it can indicate that the contractor is in difficult financial straits-especially if they say they need the cash to purchase the materials for the job.

Above all, trust your instincts. You've gotten far enough along in life that you're likely a pretty good judge of character by now. You're attuned to the various tics and tells that alert you that someone may be less than trustworthy. They won't look you in the eye. They exaggerate a lot. They won't give firm dates or times. So, don't let the tantalizing prospect of a quick fix or lowball estimate entice you into an agreement you may regret later.