Virtual private networks (VPNs) are a popular way to protect your privacy and anonymity online. However, there are some reasons why you might not want to use a VPN.
Your connection speed (or "bandwidth") may be increased or decreased, depending on how your ISP handles your data. In a situation where net neutrality exists, your email, web browsing, music streaming, and torrent downloading would all move at the same speed - some number of bits per second. However, a lot of ISPs do throttle connections depending on a customer's service plan and what kind of data is flowing.
This is possible because ISPs use deep packed inspection (DPI) to evaluate what kind of data is moving. Thence, the customer may be rewarded with high bandwidth for favored connections or penalized for traffic unfavorable, as judged by the ISP. In cases of geopolitical censorship, a connection to an country deemed "unfavorable" may be throttled to slow speeds, like dial-up, or blocked. A blocked connection would get a speed of zero bits per second.
A good feature of VPNs is that the data is compressed and then encrypted for travel through the internet to the VPN server. Most phones, laptops, and desktop computers are so fast, that VPN encryption takes an insignificant amout of time, much smaller than the time needed to send data through the network. Encrypted data cannot be evaluated by DPI, and usually is passed without throttling. If you want to force net neutrality on your ISP, use a VPN to encrypt everything you do.
VPN servers are typically on beefy servers with excellent broadband, easily capable of multi-megabit per second connections. I have tested free VPNs which are that fast, and seen commercial VPNs which, for a fair price, can manage dozens of megabits per second. The good news is that streaming VOIP or HD video requires a megabit per second or less, and just a couple of hundred kilobits per second is enough for most casual browsing.
Do not use crappy VPN services which offer bandwidths less than a megabit per second. You may see advertising claiming that the service has equipment with 10 Gbps bandwidth. However, the truth is that multiple users share that bandwidth and may only get 100 kbps per user, if too many users are on a server. Use VPNs which limit the number of users on a server. Better yet, set up your own server, with a VPN on it, and enjoy the massive bandwidth for your own usage.
A key issue for any VPN user who does sensitive tasks online (work, banking, discussing medical issues, etc) is trustworthiness of the service. Does the VPN keep logs of when a user connects and disconnects? Does it watch what a user connects to? A compromized VPN can indeed accomplish surveillance and give data to either law enforcement or criminals.
Consider what risks you can accept, and use a VPN provider which meets your needs. I often browse news and social media from environments where I am subject to censorship, surveillance, or unfriendly actors watching the wifi signals. Using a VPN prevents anyone from the local network from surveilling my activity. The VPN may or may not be compromized, but news or social media are of little value.
For tasks which require more security, I use a private server with a VPN running on it, or I use The Onion Router (Tor). In some cases, it may even be appropriate to use the private VPN server to connect into the Tor network.
When you use a service on the internet which only allows you to connect from a specific country or geographic region, you may be denied the service if you travel. Another issue may be that content you access on a service, such as YouTube or NetFlix, could be limited according to where you're accessing them from. Services check the IP addresses of their users to know where they are. Until some sort of authenticated position reporting is implemented, you may get different content or better treatment by changing your IP address with a VPN.
A down side of using a VPN is that some web services may deny you service or put you through more screening if the VPN's IP address is considered to be unfavorable. It may mean that hackers or bad actors have used the VPN to make trouble in the past. If your VPN gets on the "bad guy's list," you may be sent capchas before websites can load, or be blocked by other sites.
A rather frustrating thing happened to me once, when I used a certain VPN for evading censorship. I was able to "jump the wall" and enjoy the global internet, except for a certain forum which I needed access to for promoting my blogging and video content. The problem was quite the paradox, as I needed the VPN to reach the forum, but the forum blocked me because of the VPN's IP address. I had to use a more complicated "two hop" VPN scheme to evade both censorship and geo blocking. There is always a way to beat the gatekeepers.
Autocratic countries which survive by dishing out propaganda and disinformation to their citizens will often have restrictions on VPN usage. Users may be restricted to a very short list of authorized (government controlled) VPNs. Other VPNs, especially foreign ones, are typically prohibited. Other countries may have restrictions which prohibit VPN usage to circumvent censorship or to conceal prohibited activities.
If you are living, working, or traveling in a place with VPN restrictions, be aware of the risk. Consider using SSH tunnels or a known obfuscation method to reach servers outside of the country's jurisdiction. I am not advising against using VPNs, as I consider it to be a freedom of expression issue. Freedom of expression belongs to all of us human beeings and is not a privilege granted by any government.
Plenty of VPNs are available for free. Some are known for being fast, others make a point of being trustwothy. A few are both fast and trustworthy. Paid VPN services tend to have higher levels of quality - offering more plentiful faster servers, as well as promising to respect user privacy. Paid services certainly pitch security, meaning they work hard to keep servers from being compromised. A full service VPN could cost $5 to $10 USD per month, up to triple the cost for a premium VPN.
Setting up a VPN on your own server could cost nothing if on a an Oracle or Google Cloud free tier. Otherwise, a nicely performant self-hosted VPN could cost $5 to $10 USD per month.
VPNs are often marketed as a way to protect your privacy and anonymity online. However, it's important to remember that a VPN does not make you completely anonymous. Your ISP can still see that you're using a VPN, and the VPN provider can see all of your internet traffic. An observer outside of the VPN could try to watch traffic going in and out of the server and match pattens in the data flow, stripping away anonymity.
If you're looking for complete anonymity, you'll need to use a more secure method, such as the Tor network or I2P. Anonymity requires a means for users to blend into a large crowd, with so many members that it is impractical to look at them all to identify the user.
VPNs can be a great way to protect your privacy and anonymity online. However, it's important to weigh the pros and cons before deciding whether or not to use one. If you're concerned about your privacy, a VPN can be a good option. However, if you're looking for strong anonymity, you'll need to use a more secure method.
Here are some additional things to consider when deciding whether or not to use a VPN:
It is your own decision as to whether or not a VPN is the right tool for you. Consider the advantages and disadvantages carefully and select the option which best meets your needs.