Yes, you should turn on a VPN on your iPhone, especially when you are concerned about your online privacy and security. Activating a VPN is crucial whenever you connect to public Wi-Fi networks, like those in cafes or airports, as it encrypts your data and prevents hackers from accessing your personal information. It is also highly recommended for everyday use to stop your internet service provider from tracking your browsing habits and selling that data. Additionally, turning on a VPN allows you to access geo-blocked content and stream media from other countries, giving you more control over your internet experience.