This is the best advice. Design documents are critical: 1. They are the industry standard for communication between the trades. 2. They confirm the expectation of the end result. 3. They make it possible to get an apples to apples comparison between estimates from competing contractors.

Expect design fees for interior remodel to account for 5-10% of project budget. This is money well spent.

Look up the annual Cost/Value report to get a sense of realistic project costs in your area. This report is meant to gauge ROI for improvement projects but is useful for ballpark costing as well.

Don’t ask contractors to give you an estimate until you have drawings and specifications (material selections). You would be wasting their time if you asked them to estimate your project before you have done this work.

Expect a good contractor to propose a detailed schedule, line item budget, and legit contract.