Most contractors fail to give the homeowner written manufacturer warranties.
Most building products are not covered by warranty if not registered. Most contractors offer only standard 1 year workmanship warranties. It's easy and more profitable for contractors to sub-contract out their work to independents. Down payments given to contractors are rarely put into escrow accounts, even though New York State Law 36-A states they have to for your protection. Most are using your money to operate someone else's job.