Start with a room-by-room scope
Write down which windows and doors you want assessed and the reason for each: draft, failed seal, difficult operation, water concern, security, appearance or a planned renovation. This prevents a quote for one scope being compared against another.
Ask for the actual product specification
For windows, compare frame material, operating style, glazing and the exact performance information tied to the proposed unit. For doors, compare slab or system type, glass, frame, sill, hardware and security features. Treat broad marketing claims as background, not as the specification for your home.
Define installation and finishing
Clarify removal of the old unit, disposal, insulation and sealing, exterior capping or trim, interior casing or drywall work, paint readiness and cleanup. Ask what happens if hidden deterioration is found after removal.
Verify warranty, timing and service area
Separate manufacturer coverage from installer workmanship coverage and ask how a future claim is started. Confirm lead time and installation scheduling. A provider can legitimately serve Milton or Georgetown without a storefront there; use the published address and service-area information separately when comparing options.