VPN advertising has a habit of implying that without one, hackers are one click away from your bank account at all times, and that with one, you're essentially invisible online. Neither is quite true. Here's what a VPN actually does, stripped of the marketing.
What a VPN actually does
A VPN (virtual private network) routes your internet traffic through an encrypted tunnel to a server run by the VPN provider, before it goes out to the wider internet. Two practical effects follow from that: anyone on the same local network as you — say, other people on a coffee shop's Wi-Fi — can't see what you're doing, and websites you visit see the VPN server's location instead of yours.
That's it. It doesn't make you anonymous (the VPN provider itself can usually see your traffic), it doesn't protect you from a scam link you choose to click, and it doesn't replace antivirus software or good password habits.
Where it genuinely helps
Public Wi-Fi. This is the clearest case. On an open network at a mall, airport, or coffee shop, anyone reasonably technical on the same network could potentially intercept unencrypted traffic. A VPN closes that gap.
Accessing your home country's services while travelling. If you're abroad and need something that's geo-restricted to South Africa, a VPN set to a South African server solves that.
Extra privacy from your ISP. Your internet service provider can see which sites you visit, even if not the content (most sites are encrypted by default now via HTTPS). A VPN hides that browsing pattern from them.
Where it doesn't help much
At home, on your own trusted Wi-Fi network, a VPN adds little — your traffic is already reasonably protected by your router and HTTPS.
Against phishing and scams, a VPN does nothing. It protects the network layer, not your judgment about a suspicious link or message.
Against malware you install yourself, a VPN is irrelevant — it's not antivirus software.
Picking one, briefly
If you decide you want one, the two things worth checking are: does the provider have a genuinely independently-audited no-logs policy (meaning they don't keep records of what you did), and is the pricing sane — a legitimate VPN is a paid product, because running the server infrastructure costs money. A "free" VPN with no clear business model is often monetising you in some other way, which somewhat defeats the point.
The short version
Use a VPN specifically when you're on a network you don't control — public Wi-Fi being the main case — and don't feel like you're missing essential protection the rest of the time. The habits covered elsewhere on this site (unique passwords, two-factor authentication, healthy skepticism of unexpected links) do far more of the actual protective work day to day.