A clean-water leak that sits for two days can degrade to Category 2, and that changes the scope. That is the practical reason speed on day one matters.
Class matters just as much for the schedule. A small Class 1 loss might be dry in two days, but Class 4 losses in dense hardwood, plaster or masonry need specialty drying and extra days. Your restorer should spell out both ratings plainly and record them in the project file.
Keeping Three Parties Aligned
The project lead sends the adjuster updates, tracks approvals for each phase and tells you when the house will be livable again. Ask at the first visit who that person is and how often you will hear from them. If the answer is vague, that is worth noting.