1. Change Energy Saver settings
Most obvious option. System Settings, Energy Saver (or Battery on a laptop), drag "Turn display off after" to "Never." Mac won't sleep on its own anymore.
Catch: it's global and stays that way until you change it back. On a laptop, forget overnight and you'll find a dead battery in the morning. No way to say "never sleep, but only on weekdays" or "never sleep, but only when plugged in." It's a blunt instrument.
Makes sense for: a desktop Mac that should always stay on. A Mac Mini running Plex. A studio machine that never moves.
2. The Hot Corners trick
More of a workaround than a solution. System Settings → Desktop & Dock → Hot Corners. Assign "Disable Screen Saver" to a corner and park your cursor there.
Problem: your cursor has to stay in that corner. Move it and the effect disappears. Fragile, easy to break by accident.
Makes sense for: honestly, not much. People suggest it online, but it's not something you can rely on.
3. A system-level keep-awake app
Apps like Amphetamine and Lungo sit in your menu bar and tell macOS not to sleep using the system API. Click the icon, Mac stays awake. Click again, back to normal. Amphetamine is free with a deep trigger system. Lungo is $4 and clean.
Works well for most people. The gap: they operate at the system level, so your Mac stays awake but there's no actual user activity happening. Remote desktop sessions can still time out. Slack and Teams can still mark you as away. And if IT locked sleep settings via MDM, system API calls might be blocked too.
Makes sense for: people who want a simple toggle and don't need mouse activity or smart conditions.
4. A mouse jiggler app
A mouse jiggler moves your cursor at regular intervals. macOS sees real user activity, so it works everywhere: corporate environments with locked settings, remote desktop sessions with their own idle timeouts, messaging apps that track your status.
Shake It On does this from your menu bar with smooth, organic cursor movement and 17 smart conditions. Pause when the camera is on. Pause on battery. Only run weekdays. Only run when a specific app is open. Configure it once and don't think about it again.
For most people, this is the one. Real mouse movement plus the smarts to know when to stop.