We typically use about 7 differentiations supermarkets:
Lidl for veg, super cheap, good range of the basics but short shelf life
Aldi for some dry goods, cereals
Migros for most of the regular foods inc meat
Coop for nicer branded items
Aligro (cash and carry for restaurants like a Macro in UK) where we bulk buy tinned and dried products, sometimes meat if we're feeling rich
Intermarche (France, 30mins away) for most of the meat we buy in larger quantities for the chest freezer)
Tigros (Italy usually once a month) cheese, pasta etc
Shopping is a sport here
This doesn't include all the speciality food stuff we buy less frequently, deli type stuff that i typically pick up when i'm on my travels.