Don't get scammed], even if they're not a 'scam' per se, it's worth considering their reputation before diving into a business relationship with them. A personal referral from someone - who has ideally actually done business with them - is one of the best sources of information.
Here are some of my thoughts on why their reputation is important.
Do they care about their visibility and reputation?
Do a little online research into them to see if they are easy to find contact and location information for. Do they have a website or social media presence? Do they have business listings in usual place? Are there any reviews of their service and how good or bad are they?
Basically, you want to find out how invested they are into their business' reputation. While there might be some good folks out there working part-time "on the side", many of these types of handy-persons just don't have the same interest in preserving their reputation that a full-time business does. With no supervision and no concern for long-term effects on business, this can lead to cutting corners on materials or work quality.
Obviously, cutting corners is not a good thing. Poor work can become a potential risk for electrical fires and structural issues. Unfortunately, most of us aren't handy enough to look over their shoulder and know if they're doing something wrong. And if you're not getting inspections done on the work along the way, this is a bit of a red flag. Sure it saves you money, but how do you know it's done right?
What's the real cost?
Besides safety concerns, if something isn't done right or well you may find yourself re-doing the renovations and spending much more to correct the poor work than you would have to just have it done well in the first place. Less experienced contractors may also overlook something, creating problems mid-renovation and making the project bigger than they initially suggested.
A few more thoughts next time..