What are alternative locations and how does the re-sorting work?

You can get many items at more than one store. So besides the main store („primary“), you can add others as „Alternatives“ — or pon learns them by itself if you allow „Learn alternative locations“ and check off items. This works without location access too, once you have confirmed your shopping trip.

The benefit shows on the go: if you're spontaneously in a different supermarket that also carries an item, pon temporarily moves it into the matching group there — so your list is right even when you're not in the store you planned. Once you leave, it slips back to its main store. For this, pon only needs to know where you are right now: via location access (which stays solely on your device) — or, if you haven't granted it, because you briefly confirm it yourself while shopping.

Add alternatives: in the item details under „Where to buy“ → „Add Alternative“. The more pon knows about your stores, the better the list fits — wherever you happen to be shopping.

And don't worry: an item with several stores is still only on your list once. If you buy it at one of the alternative stores, it is done — it does not show up again at its main store afterwards. So you never have to check anything off twice, and you don't have to decide in advance where you will actually get it.