How do you plan stock for Black Friday?
Commit early on your proven lines and lightly on everything else. The expensive mistake is not running out of a good line, it is being left in January with stock bought on optimism.
In more detail
Use last year’s ratio if you have one and your own repeat-purchase data if you do not. Where a supplier allows a second order mid-month, that flexibility is worth paying a little more per unit for.
What to do about it
The customers won in that week are worth almost nothing unless something brings them back in January.
The preparation that matters happens in October. A store deciding its Black Friday plan in November is already reacting.
Discounting into a crowd where everybody is discounting wins volume and loses margin. The stores that do well have a reason to be chosen that is not the price.
The mobile app angle
This is the one week where owning a notification channel pays for the year — reaching last year’s buyers costs nothing per message.