We've all been there: it's the day before your holibobs and you finally uncover that leftover stash of sunscreen from last year, when everything in Boots was on '3 for 2' and you got a bit over-zealous with your purchasing. As you try to work out what's full and what's nearly empty, you wonder whether you should be actually re-packing this into your suitcase and taking it off to a tropical destination - or if you should be chucking it away in favour of something shiny and new from the airport once again" (Thank goodness for those last minute Boots dashes eh!) Do you risk it, or play it safe" Can sunscreen even 'go off' or is it good until the very last drop" Don't worry, because I've got all the answers and the reassurance you need to make good decisions this summer...
IF MY BOTTLE IS UNOPENED, HOW LONG CAN I KEEP IT"
The standard industry practice during sunscreen development is to test the stability of a formula under conditions that equate to three years sat on a shelf, i.e. out of direct sunlight and at ambient temperatures. This means your unopened bottle should be good for around three years - however, you don't know how long that sun cream has been hanging around before you bought it (i.e. in a warehouse and then in the store,) so I would personally recommend you only ever keep a bottle for no more than two years to be safe. I know they can be expensive, but your health (and skin) is worth so much more than a new bottle of Soltan.

IF I'VE OPE...