A recent survey has found that a third of UK employees still have 10 days of annual leave to use by the end of 2017.
Meanwhile, the average UK worker has 6 days of holiday remaining. If all those days are left unused, 134 million holiday days will be wasted. But why aren't we using them?
Hotel group Jurys Inn asked 1,000 employees across the UK about how much holiday they have left to use before 2018, and why they have not - or will not - use it.
The leading reasons people gave for not taking all their annual leave are surprising.
The majority (34%) of survey respondents said they hadn't used up all their allotted days off because they weren't sure how to use them. A further 22% said they were simply too busy to organise anything.
For 1 in 10 employees, though, taking time off wasn't appealing because they were concerned they wouldn't be able to find someone to cover their work while they were away. A holiday didn't seem worth it, because it likely meant returning to twice their usual workload.
Other reasons given included not having the money left to spend on a trip away (11%), whilst some said they had been deliberately saving up their holiday days to book something exciting - only to realise, come November, there are no holiday options that appeal to them.
The research suggests that 82% of us in employment in the UK still have unused annual leave - and, with less than two months of the year left, we're running out of time to use it.
So, if you're in that 82% - it's probably time to book something, and fast.