Quick answer
macOS has a built-in tool ("About This Mac" → Storage → Manage) that shows exactly what's taking up space and suggests automatic cleanup — usually the first step before buying a new device.
Before considering a new Mac with more storage, it’s worth five minutes to see what’s actually taking up your disk space — the fix is often simple.
The built-in tool
Apple menu → About This Mac → Storage → Manage shows a detailed breakdown (apps, photos, mail, etc.) and suggests automatic actions like offloading old files to iCloud.
The most common hidden culprits
A Downloads folder that never gets emptied, duplicate photos, and old iOS device backups are among the most common places unused space hides.
- About This Mac → Storage → Manage
- Empty your Downloads folder regularly
- Check for old iOS backups