Walking around a shop selecting goods yourself is so ordinary that it is difficult to imagine an alternative, and the arrangement is roughly a century old.
Before self-service
Customers gave a list to a clerk, who assembled the order from shelves behind a counter.
Which was labour-intensive, slow, and meant customers never touched the goods before purchase.
Credit and delivery were standard, with accounts settled periodically.
The change
Self-service stores appeared in the early twentieth century, with customers moving through the store collecting items and paying at the exit.
Which reduced staff costs substantially, and it was patented as a system.
Turnstiles, a fixed route through the store and payment at the exit were the original design elements.
What it enabled
Lower prices, since labour cost fell.
Larger ranges, since a clerk no longer needed to know where everything was.
Impulse purchasing, since customers encountered goods they had not intended to buy.
And branding becoming decisive, since the package now had to sell itself without a clerk's recommendation.
The packaging consequence
Goods previously sold loose from bulk containers required packaging to be sold by self-service.
Which transformed food packaging into a marketing medium rather than only a container.
Brand identity, which had existed, became substantially more important as the point of decision moved to the shelf.
Refrigeration and the cold chain
Domestic refrigeration and refrigerated transport enabled weekly rather than daily shopping.
Which changed purchasing patterns fundamentally, and it enabled the store format that depends on larger less frequent trips.
Frozen food arrived as a category, requiring investment in equipment throughout the chain.
The car
Larger stores with parking, sited away from town centres, depended on customers arriving by car.
Which restructured retail geography and disadvantaged those without cars.
Planning policy in several countries subsequently restricted out-of-town development for exactly this reason.
Concentration
Retail buying power concentrated as chains grew, shifting the balance in the supply chain.
Which affected suppliers substantially, and it has been the subject of competition investigations in several countries.
Codes governing dealings between large retailers and suppliers exist in some jurisdictions as a result.
What is changing now
Online ordering with delivery reverses the self-service arrangement, returning to someone else assembling the order.
Which reintroduces the labour cost that self-service eliminated, and it is why delivery economics are difficult.
Automated fulfilment and dark stores are attempts to address that, and the model remains commercially challenging.
Store layout
Product placement follows research on shopper behaviour.
Staples positioned to require walking through the store.
Eye-level placement commanding premium and being paid for by suppliers.
Confectionery at checkouts, which several retailers have removed following public pressure and regulation in some jurisdictions.
Which is deliberate design rather than accident, and slotting fees paid by suppliers for placement are a substantial revenue stream.
Loyalty schemes
Introduced to collect purchase data as much as to retain customers.
Which produces individual-level purchasing records of enormous analytical value.
The data supports range decisions, pricing, promotion targeting and, in some cases, is sold to suppliers in aggregated form.
Members-only pricing has become common, which effectively charges non-participants more for the same goods.
Own brand
Retailer-branded products manufactured by third parties, frequently including the branded manufacturers themselves.
Which gives retailers margin control and negotiating leverage over branded suppliers.
Share of own brand has risen substantially in most markets, particularly during periods of price pressure.
Food waste
Retail practices including date labelling, cosmetic standards and multi-buy promotions all contribute.
Which has been addressed through relaxed cosmetic specifications, removal of best-before dates from produce and redistribution partnerships.
The independent shop
Numbers of small independent food retailers fell dramatically as supermarkets grew.
Which changed high streets and reduced provision in areas that chains did not serve.
Food deserts, areas with limited access to affordable fresh food, have been documented and measured in several countries.
Pricing practices
Promotional pricing, multi-buy offers and reference pricing have all attracted regulatory attention.
Which followed evidence that reference prices were frequently not genuine prior prices, and rules requiring them to have been charged for defined periods now exist in several jurisdictions.
Unit pricing requirements, showing price per standard measure, exist to enable comparison and are inconsistently displayed.
Supply chain power
Concentration of retail buying gave chains substantial leverage over suppliers.
Which produced practices including retrospective charges and payment delays that investigations found were common.
Groceries codes governing dealings with suppliers exist in several jurisdictions with adjudicators to enforce them.
Self-checkout
Transfers scanning labour to the customer, which is the same logic that produced self-service originally.
Which has produced measurable losses through error and theft, and retailers have partially reversed it in some markets.
The staffing saving and the loss rate determine whether it makes commercial sense, and the calculation differs by store type.
Online grocery
Reverses the self-service arrangement by returning to someone else assembling the order.
Which reintroduces the labour cost that self-service removed, and it is why the economics are difficult.
Automated fulfilment centres are the attempted solution and require substantial volume to justify.