Area, Material, and Preparation
Adding coverage over suitable existing material and replacing affected insulation are different jobs. The cost depends on the area, product, access, and preparation your attic needs. Ask for an estimate that explains those parts of the work together. If removal or a repair comes first, it should be easy to identify. That gives you a price to consider against the work for your home, rather than an average from someone else's property.
Share the information you already have about the home and the work being considered. If you are coordinating several improvements, explain which jobs come first and who is organizing the schedule. That context makes it easier to discuss the estimate in the sequence of the overall project and identify items that need another assessment before a final scope is agreed.
Compare the Same Installation
Put the material, installation area, preparation, and cleanup beside the total on every estimate you receive. Ask about any line that is unclear, particularly exclusions and work described only as optional. A good comparison lets you understand what each contractor has priced. You can then decide whether a revised scope is needed before approving one of the proposals.
For a phased project, ask what can be completed independently and what needs to happen together. Keep the proposed stages in writing, including any work that must precede the insulation. This helps you organize a budget without making assumptions about which parts can be postponed. Your priority may be a particular attic section, but the recommendation still needs to consider how the space fits into the home.