Be proactive and wise with your window replacement project. Here are some good steps to take.
1. Do good research about installation. The difference in a good job and a bad job is about installation. You can see that on the blogs if you surf them for a while. Sizing, removal technique, caulking beads, product, trim, performance, longevity, resale appearance, and functionality are all issues. Those are some crucial details that you will think of and will matter sometime after you've learned manufacturer names and glass types and spacer options and performance estimates from a myriad of sources. There is a lot to know.
Many get hung up with "paralysis by analysis". You are looking for someone you trust with details that you will not think of. This is much easier than trying to learn all the details involved.
2. Deal with someone you trust. I try to be very transparent with my customers and work them through the process to a great deal on a great product. That is always my goal. I offer several options so that you can get the right thing for your home and your budget. sometimes I am the lowest bid and sometimes the most expensive bid.
I am always the person most likely to offer the best value in replacement windows and doors.
3. Check the internet for reviews and ratings. Here are some great places to start. Make these part of the research.
Better Business Bureau
Replacement-Windows.com (Window Forum)
4. Beware of companies that seem to close and reopen under a new name fairly regularly.
5. Beware of companies with high pressure approaches to sales. No discount is worth feeling pressured. Don't fall for it. Someone in your home too long will wear you thin. Be prepared to say no, get this, SIX TIMES. This is how many times a professional salesman is trained to ask you for your business. Know how to say no six ways, do the work to get information.
6. Beware of larger companies that use varied subcontractors. Many times these crews are not well supervised and although very fast on the jobsite, they are often not too concerned with the details. Detail consciousness takes special time and effort that few are willing to deliver at any cost. Building in a reasonable labor amount makes sense for quality of install.