Savvy shoppers can significantly cut their grocery bills by strategically timing their visits to supermarkets, according to expert David Holmes, CEO of WhatPrice.co.uk. By understanding each store's unique schedule for marking down items near their sell-by dates, consumers can bag savings of up to 90 percent on various products, particularly those with coveted 'yellow stickers'. These significant reductions typically occur in the late afternoon or early evening when managers need to clear perishable stock quickly.

While many people notice yellow stickers, few understand the precise science behind their appearance. Knowing the optimal visiting times for Britain's biggest supermarkets can lead to substantial savings for families.

Tesco: This retail giant employs a step-by-step markdown system. Initial, smaller discounts of 20-30 percent may appear from 8 am. However, the most substantial savings, reaching up to 90 percent on fresh items that would otherwise be discarded, become available around 7 pm at larger stores and as early as 4 pm at Express branches.

Sainsbury's: Sainsbury's follows a distinct reduction pattern. While the first price cuts might surface around 1 pm, the best deals, with prices plummeting by up to 75 percent, are typically found after 7 pm.

Asda: Shoppers at Asda should target 7 pm for the best bargains. Unlike other chains that have staggered discounts, Asda conducts one major round of reductions in the evening, with fresh food items often being slashed by 50-70 percent.

Morrisons: Morrisons often gets a head start, with the first yellow stickers appearing around midday. The most significant price cuts, representing final reductions, occur between 5 pm and 7 pm. David Holmes highlights that the fresh food counters—including fish, meat, and deli sections—are particularly fruitful 'gold mines' for evening discounts.

Aldi and Lidl: These discount supermarkets operate under different rules. Instead of 'yellow stickers,' they use 'red-sticker' reductions, which are put out first thing in the morning. Aldi begins its markdowns at 8 am, while Lidl starts even earlier at 7 am. This early reduction strategy is due to their products already selling quickly at low prices, eliminating the need for end-of-day clearances.

Waitrose: Markdowns at Waitrose commence around 2 pm, with the final yellow stickers, offering discounts of up to 80 percent, appearing from 6 pm onwards.

Co-op: The timing for Co-op stores can vary significantly by location. Generally, most Co-op branches make their final reductions in the hour before closing.

Beyond specific daily timings, Sunday evenings are identified as a prime opportunity for bargain hunters. With shorter trading hours and no subsequent deliveries until Monday, stores are highly motivated to clear perishable stock. While staff putting out yellow stickers may face eager crowds, patience and politeness are encouraged for a smoother experience. Crucially, David Holmes advises shoppers to only purchase reduced items they will actually use or freeze before expiry, emphasizing that the greatest saving comes from preventing food waste.