Answers

Proper ventillation is one of the most important factors in your roof lasting it's full lifespan, looking great for decades, and not creating black mold issues in your attic or crawl space. Not only do most roofing manufaturers such as CertainTeed and GAF require it allow certified installers to offer lifetime manufacturer warranties with features such as being fully transferrable and non-prorated; International Residential Code also requires proper ventillation for your roof to meet 2018 code standards. You need proper intake from a source such as functional vents in the eves with vented soffits or from smart vents. You also need proper ventillation out from sources such as a working attic fan or a ridgevent. Also be careful - more isn't always better as it can affect the air flow direction in the attic space. For example - you do not want both a running attic fan AND a ridgevent or the fan will pull air IN (not out) from the ridgevent instead of the intake locations and air will not circulate properly and will not meet many manufacturer requirements.

Ask for current copies of all their sales and contractors licenses as well as current copies of their general liability and workers comp insurance policies. Also, google them to see if they even "show up" and if they do read their reviews!

For the most value as far as peformance for the price - Leaf Relief from PlyGem. If you were looking to spend a little more to go with a helmet style guard instead of a cover I highly reccomend TruGuard. Hope this helps!

Michael's numbers are correct, keeping in mind "start at" and that is for the window itself and does not also include a high quality professional installation, spray foam insulation, high quality caulking job, custom exterior cladding, etc. Installed - if you are getting a quality window from a professional window installation company that does't cut any corners and provides lifetime warranties on the product and workmanship and warranties on the glass breakage, etc - vinyl can range anywhere from $700-1,500 and fiberglass/wood clad $1,200-$2,500 depending on the features and add ons. Big box stores, subs, builders, etc would be a lower price point but you would not get the quality most people are looking for with a replacement project on the windows, workmanship, or warranty. Hope this helps.