Why do I need to choose a slot before I place my online groceries

Latest supermarket delivery slot advice from Sainsbury's, Tesco sainsburys delivery slot Sainsbury's will begin letting its Delivery Pass customers book their Christmas delivery slots from October 16 Meanwhile, regular shoppers will sainsburys delivery slot UK supermarkets will be releasing delivery slots but there are warnings over potential shortages

sainsburys book slot When do Christmas delivery slots open? Supermarket dates for Tesco, Sainsbury's, Morrisons, Asda, and Waitrose · Supermarkets have started