Dunno. I stopped shopping at Aldi because we always needed to visit another store anyway, so for me that theory still holds. They've also taken cheap veggie chocolate milk out of the assortment, and the store next door introduced it, so there isn't any unique(ly cheap) product there that I can't get at the more expensive store and that's where we now do all our shopping. We only ever still visit Aldi when the Edeka, next door, is out of some product that Aldi has

In trying to find the exact figure earlier, I did see a paper where they classified people as one-, two-, or three-stop shoppers. Seems to be common, seeing as a lot of stores here are actually adjacent. You don't see that much in NL where I'm from. Anyway, I didn't end up finding back this figure and I don't know to which market this was supposed to apply; maybe in places like France the hypermarkets have everything without being expensive and it applies more to that? All results I found were about how amazing this company's loyalty cards are and you (the supermarket) should totally introduce them for better retention