Battery packs should be superflous but, as advanced as smartphones have become in recent years, battery life is still something they haven't quite nailed.
Some will last most of the day, others might get you through most of the evening too, but that's assuming you aren't spending all your time on WhatsApp, playing Real Racing 3 or stalking Facebook.
That's where our list of the best battery packs and portable chargers for smartphones comes in. They've been around for years so when it comes to your options, there are hundreds.
So without further ado, here's our selection of the best power bank options out there to make sure your phone keeps up with you.
Buy the Mophie Powerstation Plus (Lightning) for around £90 on Amazon.co.uk
Battery capacity: 5000mAh
The Mophie Powerstation Plus battery portable charger is available with a Lightning cable, or Micro-USB and there are also different capacities available. There is no USB Type-C option as yet.
Buy the Griffin Technology Reserve Power Bank for around £42 from Griffin.co.uk
Battery capacity: 18,200mAh
The Griffin Technology Reserve Power Bank comes in two colour options, along with a couple of capacity options. The 18,200mAh is the largest capacity available, but it is capable of charging two devices at once and it ships with both a Lightning and a Micro-USB cable.
Buy the RavPower 20100 Powerbank for around £35 on Amazon.co.uk
Battery capacity: 20,100mAh
This RavPower power bank has the largest capacity of those listed in this feature and it comes with a USB Type-C input and output, as well as a USB port. It is also compatible with Qualcomm's QuickCharge 3.0 technology and it comes with two Micro-USB cables and a USB Type-C adapter.
Buy the Belkin Portable USB Rechargeable Battery for around £15 on Amazon.co.uk
Battery capacity: 2000mAh
This Belkin portable battery pack is small enough to fit in your pocket and is compatible with any USB-enabled advice. It also comes in five colours including black, blue, pink, red and green in case you want colourful power.
Buy the Samsung Rechargeable Fast Charging Battery Pack for around £58 from Amazon.co.uk
Battery capacity: 10,200mAh
This Samsung battery pack is larger than the Belkin so you'll need a bigger pocket, or a bag. It will charge your smartphone several times over though and it offers fast charge.
Buy the Anker PowerCore 20100 for around £29 from Amazon.co.uk
Battery capacity: 20,000mAh
This Anker PowerCore 20100 battery pack is claimed to be as light as a can of soup and like the Samsung, it also offer fast charging technology. Anker says it will charge an Apple iPhone 7 nearly seven times or a Samsung Galaxy S6 five times before it needs recharging itself.
Buy the Aukey USB C Power Bank for around £34 from Amazon.co.uk
Battery capacity: 20,000mAh
This Aukey power bank has a standard USB 3.0 port, along with a USB Type-C port and a Micro-USB port. The company claims it will charge an iPhone 7 Plus or a Google Pixel four and a half times. It has Quick Charge 2.0 on board too.
Buy the PNY LM3000 from around £11 from Amazon.co.uk
Battery capacity: 3000mAh
This PNY LM3000 portable battery pack is quite a lot smaller in capacity than the Samsung and Anker options, but it has a Lightning and Micro-USB cables built-in. Sadly there isn't a USB Type-C option as yet though so you'll need to remember your USB C cable if you have a newer device.