Screen Recording

I don't know there is a limit other than the amount of free space on your drive. You could create a short recording, see how much space the resulting file takes up then approximate the limit based on your free space.

I’ve done recordings of over 2 ½ hours without issues. I think the length of recording will be more dependent on speed of CPU/processors, amount of RAM, available free storage space, and open apps. The iMac I use is a 5K 2017 27” iMac with 64GB RAM, and I record to an 8 TB external 7200RPM drive connected via USB-3. I always make sure only the essential apps are open before i begin recording.

The screen recordings I do are for remote learning of Adobe Lightroom and Photoshop and I record both audio and video. These are pretty processor and memory intensive apps, so less demanding apps may not require as much memory etc. I hope this helps.