It's hard to be an internet user without being bombarded with ads for VPNs. Be it on online videos, podcasts or even the occasional TV ad, VPNs are headed for the mainstream.
But with the companies making big claims that lack nuance, do you really know what your VPN subscription is capable of? We run through the main questions you might ask before shelling out for a year's subscription.
Test yourself with five questions on what VPNs can and can't do.
Lots of VPN companies advertise the fact that you can't be tracked when you're using them. What they don't say is that it requires you to do more work than simply install and run a VPN. The good news is that your IP address, which is the unique set of numbers assigned to your computer or smartphone, is hidden from the services you're visiting, and every time you connect to your VPN this address changes.
However, it can't stop websites tracking you in other ways. VPNs don't prevent cookies - small files that keep tabs on where you've been online - from being used when you visit websites. This means that using a VPN won't stop you from getting personalised ads and also means that Facebook, Google and other services still know what you're up to even if you aren't specifically visiting Facebook and Google's websites.
You can improve the situation yourself by using 'Incognito' or 'Private browsing' in your web browser. Once you close a private browsing session, all the cookies and other data are deleted and the next time you start a session, you're starting from scratch. You can also disable as much tracking as possible and turn off cookies, but these might make websites harder to use and they might forget your settings, or stop working entirely.
But even then, the most advanced way of identifying a device is by using 'fingerprinting' techniques, which take into account a huge number of individual factors about your device and your web browser to identify you as a unique user, and serve you ads and track you. You can find out how your own device fares by using the .
In short, yes, a VPN decreases your ability to be tracked online, but the way to truly avoid being tracked by companies is to simply not use the web whatsoever. A VPN is not a privacy panacea.
One of the key selling points of a VPN is the ability to access content that isn't available in the country you're currently in. For example, being able to watch the US version of a streaming service when you're in the UK so you can access different films and TV programmes.
This is great in principle, but in reality we've found that many VPN services struggle to keep up with the streaming services' efforts to thwart such VPN usage. After all, accessing a streaming service in this way is technically against streaming providers' T&Cs (although we haven't ever heard of someone having their account removed for doing so).
None of the VPNs we tried in our snapshot lab test were able to access all seven of the streaming services we used on their first try. It might take a few attempts to get the content you want when you're using a VPN to access streaming services.
VPNs promise high-speed connections with unlimited data. Since you still need to send data via your internet provider before it reaches your VPN provider, you will always be limited to the maximum speeds that your ISP can provide and will still have to abide by your ISP or mobile provider's monthly data limit.
If you have a very fast ISP, such as a top-tier fibre connection, a VPN can slow you down. We found the average download speed of VPNs was 212Mbps. In fairness to VPNs, this is far faster than what the majority of the UK's broadband customers can achieve. But if you have a super-fast internet connection, you might find your speeds drop when you're using a VPN.
Another thing VPN providers tell you is that only by using a VPN can you protect yourself on wi-fi networks. Some even claim you should use a VPN on your home network.
There are two parts to this. If you're connecting to a wi-fi network that requires no password and has no security, a VPN will ensure that anybody looking to take a peek at your data won't be able to. This sort of wi-fi network isn't particularly common, but it can also be an easy way for a fraudster to steal your data.
At home, things are a bit different. There's no doubt that adding an extra layer of encryption isn't a bad thing, but VPN companies that tell you to use their services 100% of the time are likely overstating the risks of using your home wi-fi network. Modern routers, whether or not there are security issues with their passwords or software, use strong encryption when you're connected to them. This means it's extremely difficult for anybody trying to steal your data to do so. It's far easier for someone looking to steal data to do it through a phishing attack or via scam phone calls and emails.
A VPN will undoubtedly make it more difficult to hack your wi-fi, but given how challenging it is already, and considering it's unlikely that an individual going about their normal routine at home would be targeted in this way, it's not worth buying a VPN simply for this reason alone.
This might sound obvious, but VPNs that overstate their credentials might make you believe all your data is safe. This isn't true.
If your data is stolen from a business you've used - for example, an airline whose website has been hacked or a social network whose databases have had a major leak - a VPN cannot help you with this at all. If you give another business your data, whether you're using a VPN or not, you are now trusting that business with your data.
Some VPNs come with additional tools that claim to monitor the 'dark web' for data about you that's been leaked, which is handy - you can use this to work out whether you need to cancel credit cards or change your passwords.
Switching on a VPN isn't as simple as offloading your worries to another company. You need to trust that the company will do the right thing. Instead of trusting your ISP with your data, you're now paying a VPN company to handle your web habits instead
It's impossible to know what goes on inside a VPN company's systems (although many advertise the fact that they have had approval from third-party auditors), and while the big brands are unlikely to be siphoning off your data and selling it to the highest bidder, small, fly-by-night operations that offer a free service may do just that.
What's more, our tests have found that VPN software itself isn't always airtight. The majority use tracking tools to learn more about their users - a fact we discovered in our testing - and others also had minor security problems.