While iMacs are certainly more expensive than computer monitors, if you already have an iMac, you can save yourself the extra money by not having to go out and buy a second monitor.

If you have an iMac made in mid-2011 or later, here is how you can use it as an external monitor.

New iMacs can use Universal Control, but or iMacs from 2009 to 2014 can be used as external monitors when running certain versions of macOS.

Here is the problem. My girlfriend's iMac was hit with a power surge, after which her father attempted to fix it. The result, one thoroughly borked imac. Fortunately the monitor survived unharmed ...