The main holiday sales event no longer occupies a single day. It stretches across weeks because concentrating demand into one date is expensive for everyone involved in fulfilling it.
Warehouses cannot absorb a single peak
Fulfilment centres are staffed and equipped for a planned throughput, and a one-day surge would require capacity that sits idle for the rest of the year.
Spreading the same volume across several weeks lets the same staff and the same conveyors handle it, which is dramatically cheaper than building for the peak.
Delivery networks face the identical constraint, since vehicles and drivers cannot be added and removed at short notice.
Early promotion is competitively forced
Once one large retailer opens its promotion earlier, others must respond or watch the first purchases of the season go elsewhere.
Holiday budgets are broadly fixed per household, so a sale that captures spending early captures it permanently rather than merely shifting the date.
The result is a ratchet: the start date moves earlier each cycle and rarely moves back, because retreating means conceding the opening weeks.
Stock is committed long before
Holiday inventory is ordered many months ahead, often before the previous season has finished, and manufacturing and shipping timelines make later adjustment impossible.
By the time promotions begin, the quantity is fixed and the only remaining decision is how quickly to sell it and at what price.
Starting earlier gives more weeks to move a fixed quantity, which reduces the risk of holding it into January.
Extended events change the discount pattern
A longer event means offers rotate rather than all appearing at once, with different categories featured in different weeks.
The deepest reductions no longer cluster on a single day, and a shopper watching only that day sees a smaller share of what was available overall.
It also means an item discounted early may be discounted again later, which was rarely true when the event lasted a weekend.
What the stretch means for shoppers
Popular items in limited supply still sell out, so waiting carries a genuine risk on anything specific rather than substitutable.
Broadly stocked goods behave the opposite way and often reach their lowest price late, once the remaining stock must clear before the year ends.
Knowing which of the two a purchase falls into matters more than knowing which day of the event to shop. A specific model in one colour is a scarcity purchase; a category with a dozen acceptable options is not.