What would happen if your phone or tablet ran out of charge? For most people, it doesn't bear thinking about, so we've developed what we think of as sensible habits to make sure it never happens. We might plug the phone in as soon as we come home, or leave it on charge overnight. However, new figures have revealed that these habits might not be as sensible as we think - and could be costing us dear.
Data analysis commissioned by insurance provider Row.co.uk reveals that the increase in ownership of mobile phones, smartphones and tablets has resulted in more than a £900 million being spent on energy every year.
This has much to do with the fact that nine out of ten of us have a mobile phone - and two thirds have a smartphone. It's also partly because the launch of the iPad in 2010 sparked interest in a whole new kind of device - and now there are 15 million of them in homes across the UK.
Between them, these gadgets use as much electricity as all laptops, desktops and printers put together. In fact, only our TVs, fridges and washing machines use more.
Put another way, consumption by all the chargers across the UK is equivalent to the total electricity consumption for a year for the cities of Birmingham and Bradford combined.
You might think that this is just a reflection of our changing lifestyles. You could argue that these gadgets are less power-hungry than things like laptops and desktop computers, so they are helping keep our costs down.
However, it's essential not to forget the effort we are putting in to avoid ever running out of charge. If you leave your gadgets plugged in when you're not using them - especially if you plug them in overnight - you could be wasting a small fortune
Tests carried out by researchers from the Berkley Lab at the University of California found that a fully charged phone continued to draw 66% of the power it consumed while charging, so a significant proportion of the money we spend on charging our gadgets is actually wasted.
A previous study by EON put the level of waste at an average of £60 a year. It also concluded that overcharging batteries also reduced their lifespan, and meant gadgets and computers would need replacing more frequently.
Richard Waters of Row.co.uk said: "We all plug our gadgets in on a daily basis with little thought of the cost. Our analysis reveals for the first time how much Britain is paying for keeping our phones and tablets powered up."
What can you do?
The EON study found that even when people were told that they were wasting their money by leaving gadgets plugged in, one in ten admitted they wouldn't change their habits, because they couldn't be bothered.
Making a change doesn't have to be hard. It's definitely worth considering whether you can find a smaller window for charging, which won't waste as much energy. Assuming, for example, you need to charge for two hours a day, you could consider plugging in between dinner and going to bed, and leave the phone unplugged overnight. Alternatively, if you have a long drive to work, you can plug them into your car charging system while you commute.
There will be those for whom these changes are worth it in order to save £60 a year, and those for whom it's not.
If it would take a bigger saving to get you to change your habits, then you could consider changes that remove the cost of charging from your own energy bill entirely.
If, for example, you commute by train, check whether there are any sockets you can use while you travel. Likewise, cafes and restaurants will have plug points that they use for cleaning, so while you're having a coffee, the coffee shop could be charging your phone. That way you're not only avoiding waste, you're finding someone else to pay for your electricity consumption too.
This isn't a solution for the faint-hearted, because you will have to risk running out of power if you can't get to a plug point in time. There's also the risk that at some point a restaurant owner is going to ask you to unplug your laptop and go home.