It’s time to upgrade to VPS hosting when;
1. You need full root access to install and maintain your own applications on your server, and
2. You need additional server resources like RAM and Disk Space that is not offered by Shared Hosting.
3. You need the highest level of access to install and maintain your own applications & policies on your server.
4. You don’t need your websites/applications to get bogged down by the resource limits of Shared Hosting