For the average user, with a decent Internet speed, the answer is: Yes, you should turn your VPN on every time you are online. We mentioned speed because a VPN reduces the speed of your connection. It may reduce a bit or even take a big chunk, it depends on the VPN provider you get. But the speed loss is compensated by the online safety a VPN provides, in more situations than you think.
Why should a VPN be always ON?
Obviously, some situations are riskier than others. For instance, using your laptop or smartphone on public Wi-Fi without protection is one of the worst things you can do. The owner of the coffee place, or restaurant (or wherever you are) is going to have the power of checking your online activity. Also, someone who knows what they're doing will be able to do that. It's actually more likely that it's not the owner, but someone else. There are more and more hackers searching for victims on public Wi-Fi hotspots. It's easy for them to get access to passwords, bank accounts, etc…
Even from the comfort of your home, everything you do on the Internet is being monitored by your ISP and it may be sold to marketing agencies. Those are willing to pay a lot of money to get your browsing history. That way, they see what kind of products you're interested in and they will know what ads to use to brainwash you. But from the moment the VPN is on, no one can see a thing, not even the Internet Service Provider.
There are plenty of other situations where the encryption of a VPN can be an advantage. For example, activities like torrenting unprotected are a magnet of attention. Your ISP will handle any data they have from you to authorities or film studios. And we're sure you heard about what happens next. That's right, fines.
What if I forget to turn it on sometimes?
That is no excuse anymore. Nowadays, a proper VPN software comes with the option to turn on the software automatically when you start your computer. That's a very smart tool that was designed so that users don't even have to think about it.
When I entered the world of VPNs, many years ago, a friend told me a thing that I will never forget: “You should turn your VPN on even for breathing”. A bit of an exaggeration, but that's probably why it stayed in my head. Today, that sentence makes more sense than ever. There are agencies fighting for our private data, to profit or simply to have power over us. It doesn't matter if we are simply checking the mail, downloading a song or browsing a product. Everything we do online is profitable information to someone and they will try to see that activity.
After reading this post, I'm sure you agree that losing a bit of speed doesn't sound that bad anymore. It's completely worth to have a small dent on your Internet speed and have your VPN protecting you at all times.