Estimate the time you need to have the PDF and/or book delivered!
Most organizers collect contributions over 15-45 days. A shorter timeframe of 3-7 days is possible if you have a small group of motivated contributors.
Most organizers review and edit over 4-12 days, although 1-2 days is certainly possible.
Regardless of whether you purchase a physical book, a PDF is available immediately. Organizers under a time crunch often share the PDF first before presenting the book later.