So what is the 'right' number of times you can re-wear an outfit?
There's probably a part of Scottish First Minister Nicola Sturgeon rolling her eyes at the consternation about her repeat wearings of a certain red suit - 11 and counting. How come Alex Salmond's 111 outings in the same suit never attracted a murmur?
But the grandstanding pragmatist in her knows that a woman who's gaining publicity for frugal husbandry of her wardrobe is a politician who's creating a powerful impression of decisiveness and economic prudence, even as she advises her fellow Scots to vote for an outcome many argue is reckless.
Listen, it's r.e.d. It's by a Scottish design duo called Totty Rocks. If she'd wanted it to slip under the radar, she'd have gone for something wishy-washy, in grey.
Then there's Theresa May's "lucky" Vivienne Westwood suit: three grand airings in the past 12 months. It's not as affordable as Sturgeon's, but it is tartan. Tread carefully, hons. Too many sightings - whatever "too many" in this context is, but 11 is probably getting there - and the commentariat will accuse you of being slovenly, or arrogant.
Unless public female figures exhibit at least a trace of vulnerability about the way they look, they risk being mistaken for an automaton.
This is the Faustian pact women in the public eye must make. Either you ignore the basic sartorial rules in the belief that there are more important things in life, and risk speculation that your memory's going, or you use your aesthetic collateral, and take it on the chin when it gets abuse.
The public and media are volatile. The Duchess of Cambridge is still hugely popular, so when she wears something more than once, such as the red Luisa Spagnoli suit that has made four public appearances in the past six years, she's practically deified for keeping it real. But if she begins to get backwash from the criticism around William's perceived reluctance to take on more royal duties, her recycling might be interpreted as a sign that she's lost interest in people-pleasing.
Diana used to pass her clothes on to her sisters - but it's hard to see Pippa embracing Kate's cast-offs, so the Duchess is caught in a delicate spin cycle.
It's probably a generational thing. The Queen, whose tight reign on household spending is legendary, could probably wear the same two outfits in rotation for the foreseeable and we'd all think: "That and the Tupperware - adorable." Princess Anne gets away with it, too, up to a point. The payback is that, despite being one of the hardest-working royals, she's liable to get knocked off the front pages by someone - anyone - wearing a better frock.
Millennials generally don't do re-wears, partly because they faithfully document their recreational time on social media and feel their "public" demand constant image reinvention, and partly because they've only ever known cheap clothing. I dug out a 20-year-old copy of Elle the other day and spotted a floral T-shirt from Morgan de Toi, a French chain, that cost £38 ($67).
Today, a similarly decorative T-shirt with ruffled sleeves from an equivalent store, Mango, costs £19.99. It's hardly surprising that Inditex, the Spanish giant that owns Zara, has just posted an increase in revenue but a 1 per cent slide in profits.
We're shopping more than ever - when we're bored, lonely, depressed or when, glass of pinot noir in hand, we're too tired to summon the energy to do anything more creative.
Nine in the evening has been renamed wine o'clock because that's when retailers report a nightly spike in sales. Was anyone under 45 surprised by the study conducted for M&S last year which found that 46 per cent of the clothes in the average wardrobe are rarely taken off their hangers?
The general drift, then, is towards wearing our clothes fewer and fewer times. Yet some women have made a virtue of constancy. Anna Wintour repeatedly wore the same black boots and Prada dress at the shows recently; Christiane Arp, editor of German Vogue has been wearing white shirts and black trouser suits since at least 2005; Emmanuelle Alt, editor of French Vogue, is almost always in black drainpipes and a pea-coat, albeit in subtly recalibrated versions. None is embarrassed about recycling a coat from three years ago. Note the absence of traffic-light red.
Emmanuelle Alt never strays far from her signature look. Photo: Getty Images
It's called a uniform, and in the innermost sanctum of fashion circles, it is much admired for being a far more distinctive style statement than perma-change.
A uniform indicates decisiveness, discipline and clarity of vision. It says you've been round the trends block and emerged on Self-Knowledge Street. It's interesting how many women with vast sartorial choices say they're happiest when they travel and only have a suitcase of options to choose from, partly because it cuts down decision-making, partly because we all tend to pack the items we love most.
So is there a formula for an optimum amount of clothes? It depends on your lifestyle. A general mantra is only ever to buy what you really love.
Reduced to a mathematical equation, if you apply the five tops to one bottom principle (on the basis that tops always attract more eyeballs than a black pair of trousers), then even if you just had two pairs of trousers in different colours and 10 tops, that's potentially 20 different looks.
Add some bags, bangles and shoes, and it doesn't take long - or that many items - to get to 100 variables, or three months without a repeat. That would mean wearing the same look just four times in a year. Who'll tell the First Minister?
- The Telegraph, London