The short answer
No universal project duration is safe without a defined opening schedule and provider plan. Ask for assumptions covering count, method, access, damage, finish work, weather, permits or inspections, daily closeout, and how changes affect the schedule.
- Opening count and variation
- Insert or full-frame scope
- Access and household constraints
- Repairs, finish, weather, and inspection dependencies
- Change-order process
Sources
Sources
- How to Avoid a Home Improvement Scam — Federal Trade Commission
- Window Installation — U.S. Department of Energy