As with most people, you probably have a list of "To-Do's" around the house that you are meaning to get to; replacing the roof, replacing a door or some windows, upgrading the bathroom, painting the siding, etc.
Then, just as you were about to seriously start investigating how to get one of these projects done, a sign goes up in a neighbors yard, or the phone rings and a young lady asks you about the condition of the windows in your home. What to do? While telemarketers, door knockers and job signs do not disqualify a home improvement company from being good and trustworthy, neither should it give them much credibility.
Being in the residential construction industry for more than 34 years has allowed me many opportunities to see the good, bad and ugly of the industry. Many times clients and fellow contractors are eager to share their "war stories" in regards to poor design, poor workmanship, poor communication, improper use of materials and other missteps of an unscrupulous or under-qualified contractor. In comparing many stories, I have observed what I would term some common characteristics that might help you identify a risky contractor before the papers are signed. While this is not a substitution for your gut feeling and common sense, these contractor practices might help you assess your chances of a good construction experience vs. a poor one:
Often these types of contractors are disgruntled former salesmen who often just sell a job and hope that their subcontracted installers will take care of all the production and quality control, with little to no oversight by an accountable Production Manager. Others might be installers that are marginally capable technicians but have the guts to go knock on doors. You will find most of these new (less than 3 years old) companies to be very competitively priced but have no ability to solve complex problems or even recognize them. They typically lack in design and selections experience and are often not able to warrant their work.
As with all purchases, you need to do your home work before signing on the dotted line.
If you don't do your home work and ask the hard questions you will, most likely, end up with a mess, and what's worse, paying for it twice—one to have it done wrong and one again to have a proven contractor fix it. It's not worth the risk.