If VPN marketing material is to be believed, the only way to stay safe while online is to keep your VPN on at all times. Is that really necessary, though? What are the positives about always having your VPN on, and are there any negatives?

Unsurprisingly, the answer isn't as simple as marketers would have us believe. While VPNs are a great tool to prevent online surveillance, there are some noticeable drawbacks when using them. Let's go over the pros and cons of leaving your VPN on all the time.

Why We Use VPNs

The case for always having your VPN on is simple: marketers are collecting your data every second you're on the web, and a VPN is a powerful tool that will stymie their efforts. It's not the only tool---you should also use incognito mode if you want to browse the web anonymously---but it gets a good portion of the job done.

This is due to the way a VPN works. When you use a VPN, you connect to a server operated by the VPN provider and only then to the rest of the internet. This has two upsides: for one, the sites you connect to can only see the server's IP address, the set of numbers that works as a locator for your online connection and by extension your physical location, meaning you appear like you're somewhere else.

Hiding your location is only the first trick, though a powerful one as a lot of tracking uses your IP address to determine where and who you are. The second ability of VPNs is that they also encrypt your connection, making it so your web browsing can't be retrieved by either the sites you visit or your ISP (internet service provider).

This last one is the biggest issue if you live in a country that doesn't have laws in place that prevent ISPs from selling your browsing data, the United States being the prime example. Without a VPN, that data is laid bare for your ISP to see and sell to marketers.

Why Using a VPN All the Time Might Be a Good Idea

As a result, if you live in the U.S. or a country that has similarly constructed laws, you may want to prevent your ISP from seeing, storing, and selling your browsing data. In these cases, a VPN is your best line of defense---though again, you should use it in conjunction with incognito mode.

Related: How Advertisers Track You Across the Web (and What You Can Do About It)

As such, it's probably a good idea to have it on all the time. It's not like the data gathering ever stops, so neither should your VPN. You may even want to set up a VPN router so your whole network is protected at the same time without any further input from you.

Even outside of the U.S., though, there's a case to be made for having your VPN on all the time. Even if your ISP isn't selling your data, internet giants like Facebook, Google, and others most certainly are. Using a VPN will frustrate those efforts, though techniques like browser fingerprinting mean that they'll still have some idea of who you are.

The Drawbacks of Leaving Your VPN On All the Time

We've established that VPNs do wonders for your privacy, let's now discuss the cost. This falls into two sections: annoyance and speed. There's also a third, the actual price you pay per year, but let's assume you already have paid for your subscription and are otherwise happy with your VPN.

VPNs Get Annoying

The annoyance part is simple to explain: when you use a VPN, you're likely going to run into blocks and other obstacles. For example, Netflix won't always work since it can detect VPN use and will block you.

You can get around that by using a VPN that can unblock Netflix, of course, but even then it may not always work. There's also the issue that if you use your VPN to connect to another country, you'll be redirected to the site version for that country when companies maintain several sites.

For example, you might see a different selection of products on Amazon or your bank may not let you access your account because you're apparently logging in from another country. Steam will likely have you re-enter your account credentials to access your games. Often, sites may display in a language you can't understand and you have to somehow find a button that changes the settings to English. It can get pretty annoying.

Speed Matters

However, the biggest issue with leaving your VPN on all the time is that of speed. No matter how you cut it, VPNs will slow down your connection. The best ones won't do too much damage, but some others will bring it back down to a crawl. Now, this usually isn't too bad an issue if you have a good connection to begin with, but if you don't, VPNs are more curse than blessing.

On top of the issues above, sites may also take forever to load, videos may get stuck in a buffer, and every other frustration you'd associate with slow internet speeds. There's no good way to fix these problems either, besides signing on to a better VPN; if you're past the refund window on your current subscription, you're going to lose money.

Should You Leave Your VPN on All the Time?

All in all, it's hard to determine whether or not your VPN should always be on. We'd like to say "yes," but there are difficulties when doing so, and it depends on your use case and network setup. If you can deal with the occasional lockout and don't mind reduced speeds, check out one of our best VPNs and browse securely. If not, though, you may want to only switch on your VPN when you're doing something sensitive online, like torrenting, and have it off the rest of the time.