I don’t think that you have to do it day by day. You can do it for all days in your
Not every day, but three days ahead for the length of your reservation. Beginning at that time, you can book ahead every day for your whole trip.
MDE will know the length of your park reservations.
This is from MDE:
“When You Can Purchase
Lightning Lane Passes
Guests can start purchasing Lightning Lane passes here in the app for days they have valid theme park admission beginning at 7:00 AM Eastern Time on their first day of eligibility, defined as follows:
Guests of Disney Resort Hotels and Other Select Hotels*
Seven (7) days before the first day of your Resort stay for your length of stay (up to 14 days).
Guests with date-based theme park tickets (which require you to choose a start date at the time of purchase)
Three (3) days before the first day of your ticket, for the total number of valid admission days of your ticket.
Guests with other ticket types**
Three (3) days before your park visit.
Annual Passholders**
Three (3) days before your park visit.
Depending on your admission type and the date of your visit, you may need a valid theme park reservation for the same park on the same date.
Purchase Lightning Lane Passes
Lightning Lane passes are nonrefundable and nontransferable. Lightning Lane passes, attractions and experiences may vary by date, are subject to change or closure, are limited in availability and are not guaranteed, and may not be available at all on the date of visit or at the time you make a selection. Price, terms and entitlements are subject to restrictions, and change or cancellation without notice.”