What is the difference between shared hosting and a VPS, and when should I upgrade?

Shared hosting: many customers share one server and one OS. You get a control panel, PHP and MySQL preconfigured, backups often included, and no root access.

• Pros: cheap, little to maintain, support handles the server.
• Cons: noisy neighbours, strict limits (CPU, processes, memory, execution time), limited PHP extensions, no long-running processes (queue workers, WebSockets), restricted cron, often no SSH or Composer.

VPS: a virtual machine with dedicated RAM/CPU slices and root access.

• Pros: install anything (Redis, Supervisor, Node, Docker), tune PHP-FPM and MySQL, run workers and schedulers, predictable performance, multiple isolated sites.
• Cons: you handle updates, firewall, backups, monitoring, SSL and email deliverability. A broken server is your problem.

Signs you should move

• Resource limit errors (508, 503, "entry processes") at normal traffic.
• You need persistent processes: Laravel queues, Node apps, websockets, scheduled jobs under one minute.
• You need a specific PHP version or extension, or a different database.
• Compliance or isolation needs.

Middle options

• Managed WordPress/Laravel hosting (you get tuning and backups without sysadmin work).
• A VPS with a panel (e.g. a free or paid server panel) or provisioning service that sets up Nginx, PHP and certificates.
• Platform services (PaaS) for deployments from Git.

If you migrate: start with 2 vCPU and 2 to 4 GB RAM for a handful of small sites, add swap, enable automatic security updates (unattended-upgrades), use SSH keys only, a firewall, and offsite backups from day one. Move one site first, test, lower DNS TTL, then cut over.

Small sites that are stable and low traffic do fine on good shared hosting; do not move only because VPS sounds more serious.