Try it before you install
You can run Linux off a USB stick without touching anything on your Mac. Whether that's worth doing depends on which model you have.
How a "live" USB works
The installer USB isn't just an installer — it's a full working Linux desktop that runs straight from the stick. You can browse the web, open the settings, try the Touch Bar. When you're done, you reboot, pull the stick out, and macOS is exactly as you left it.
What a live session is good for
- Confirming Wi-Fi connects.
- Feeling the keyboard and trackpad.
- Seeing whether the screen, brightness, speakers, and Touch Bar behave.
- Getting a feel for the desktop before committing.
If you have a Mac without a Touch Bar, or a 2016 / 2017 Touch Bar MacBook (T1)
Live USB is a cheap, easy preview. Write the stick, hold the Option key while powering on, pick the USB in the boot menu, click around for half an hour. If it feels right, install. If it doesn't, you've lost nothing.
On these machines, do this before installing. It's the cheapest insurance available.
If you have a T2 Mac (2018–2020)
Honest catch: a live boot needs almost all the same preparation as a real install. You need the T2-patched Fedora ISO, an external USB keyboard, the Wi-Fi firmware extracted from macOS first, and Secure Boot already lowered. The casual 10-minute test isn't really possible.
That said — if you've done the prep anyway, booting the stick live before clicking "Install" is a smart final check. If something is going to be broken, this is where you find out.
When to skip live mode
If you're planning to dual-boot (keep macOS alongside Linux), the live preview is optional. Dual-booting gives you the same safety net with less ceremony: your macOS stays, Linux gets a slice of the disk, and at every reboot you choose. If anything goes wrong with Linux you boot back into macOS in 30 seconds.