Since the first lockdown came into place over a year ago, so many of us have all but forgotten about our make-up bags, with skin tints and hydrating serums replacing a full face of daily make-up.

Now, with the weather brightening and greater freedoms looming, dipping back into that make-up kit feels like an exciting prospect, with experimentation and expression firmly back on the cards.

But if you haven’t opened that bottle of foundation since last summer, it might be worth checking its expiration date. Make-up does not last forever, especially once opened and, to make matters more confusing, different formulas have different lifespans.

“The little 'open jar' icon on your make-up’s packaging tells you when the formula will start to degrade in terms of performance and efficacy, but also can indicate when the preservatives and stabilisers in the formula can start to break down," explains Warren Dowdall, senior pro artist at Bobbi Brown.

"This may lead to bacterial growth, so it’s key to keep an eye on when your products are coming to the end of their lifespan," he says. "A quick fix is to pop a date sticker on your products once you’ve opened them so you know exactly when to replace them.”