A dog does not skip dinner and a litter box does not wait. Pet supplies already reorder themselves on a biological clock - a subscription only puts the billing on the same clock, so the reorder stops depending on whether the owner remembers.
The pet sets the cadence
A 30-pound dog works through a 24-pound bag of kibble in about seven weeks. That arithmetic, not a promotion or a marketing calendar, is what sets the reorder date.
Known subscribers, known pallet orders
Litter and kibble are bought by the pallet and stored by the square foot. A subscriber count weeks out tells you what to bring in before it ties up the warehouse.
Repeat orders carry the freight
Heavy, low-margin goods only work when the customer keeps coming back. A subscriber who reorders nine times a year spreads the acquisition cost thin enough for kibble margins to survive it.
Spring demand arrives all at once
Flea and tick season lands hard in spring, and a puppy's first year runs on a fixed schedule. A six-month prepaid plan collects that run up front instead of one month at a time.