It is recommended to purchase a VPS if:
You need more control over your hosting environment.
Your website or application requires more resources than those offered by shared hosting.
You want to install specific software or custom configurations.
You want a scalable solution to adapt to the growth of your project.
You are looking for a balance between cost and performance, as VPS are usually more affordable than, for example, dedicated servers.
In summary, a VPS is an excellent choice when you need more control, flexibility, and resources than those offered by shared hosting, but you still do not require a full cloud or dedicated server.