For 10 years, Lizi Hall has been doing most of her shopping at Lidl - and she's learned how to get the best value from its rewards scheme.
"We've got it down to a bit of an art," Lizi says. "The loyalty system for me really did work."
Every month, the 44-year-old from Chichester would spend at least £250 on groceries for her family - and in return she'd receive a 10% discount on her next visit. Lizi would then do a big shop to make the most of that voucher.
She also collected other perks along the way. When she spent £50 in a month she'd claim the free vegetables on offer - often opting for a 7kg bag of potatoes, priced at £4, to maximise the saving.
But this week, the discount supermarket chain overhauled its loyalty scheme, scrapping spending-based freebies - including free pastries and vegetables - in favour of a points system similar to those offered by many other supermarket chains.
Under its old scheme, Lidl shoppers had to redeem rewards within a limited time frame, with the freebies usually expiring within a week.
Now, points earned through shopping at Lidl can be redeemed for less time-limited products or money-off coupons in its app.
Points will now be accrued at a basic rate of one point per £1 spend, but Lidl says there will be lots of opportunities to earn bonus points.
Some shoppers told the BBC they welcomed the chance to build up more points because they didn't spend enough to unlock many deals under the original scheme.
But others aren't happy. In Lidl groups on Reddit and Facebook, there are complaints the new Lidl Plus scheme isn't generous enough.
Many point out they now need to spend a lot more to get a free bakery treat, where previously they only had to spend £10 in a month.
Lizi says the updated scheme won't keep her "loyal to Lidl" and now plans to switch between there and Aldi, keen to still find savings as inflation and global conflicts increase prices.
For London students Amelie Harding, 20, and Madeleine Mourgue d'Algue, 19, some of the best deals are connected to the personalised offers in the Lidl app, like getting discounts on veggie burgers - something Amelie often buys.
"I really only shop at Lidl," Amelie says. "I really like the loyalty card."
Although she feels it's a shame she'll no longer be able to get a free bakery item each month, she is looking forward to collecting points.
Lidl told BBC News its switch to a points-based system "allows our customers to choose the rewards that suit them best", adding shoppers can now "choose exactly how and when to redeem their savings".
It is the latest supermarket to make changes to its loyalty scheme.
So, at a time when food prices are rising rapidly, do supermarket loyalty schemes still actually have any connection to loyalty?
Retail expert Catherine Shuttleworth says customers pay careful attention to changes to supermarket schemes.
"When you meddle with loyalty schemes, you do so at your peril," Shuttleworth warns. "You can give away lots of points, but if you're £5 dearer than your competitor, people will swap anyway."
Research by retail analysts TCC Global found most shoppers are signed up to four or five loyalty schemes, and Shuttleworth says people focus mostly on the final price on their receipt.
Lidl's old scheme was "very rewarding", says Seb Hill of TCC Global, but the new scheme will bring it "in line with other retailers".
One of the most tangible ways shoppers can save money using loyalty schemes is when two different prices are advertised - one for all customers, and a cheaper one for loyalty scheme members. This system has been adopted by Tesco, Sainsbury's, Co-op - and Lidl too.
Some customers argue two-tier pricing could be artificially pushing up prices for all customers.
However, in a 2024 report the UK's competition watchdog, the Competition and Markets Authority, said loyalty schemes do offer genuine savings, and found "very little evidence" supermarkets were inflating prices to make promotions look like a better deal.
Meanwhile, some supermarkets allow points to be transferable. Those using Tesco's Clubcard scheme can spend their points on vouchers for restaurants and attractions, while Sainsbury's Nectar points can be transferred for Avios points towards free flights. And Waitrose offers its long-standing loyalty perk - a free hot drink - as a unique benefit.
For Steven Rowan, 64, from Glasgow, loyalty schemes do not influence where he buys his groceries.
Steven, who got in touch via BBC Your Voice, likes to shop at Aldi, Farm Foods and Iceland, which don't have loyalty cards but which he feels offer better savings. According to Which? Aldi was the UK's cheapest supermarket in April, with Lidl in second place.
Student Nick Tang, 19, liked his free pastry from Lidl each month, but says he doesn't mind no longer getting it - as the store is cheaper than most rivals.
As he puts it: "I'll keep shopping in Lidl."
