A sold roof is a chain of outside parties keyed to a moving date
The part of roofing that rented tools handle worst is production, where your schedule depends on people who do not work for you.
Your office coordinates suppliers, dumpster haulers, permit offices, inspectors, and subcontractors for gutters and skylights. On insurance jobs, add an adjuster and sometimes a mortgage company.
None of them can see your calendar. Each date change means a round of calls, and each call is a chance for somebody to miss the update.
Many roofing apps are strong on leads and estimates, then hand the sold job to a calendar, a group text and a spreadsheet of material orders.