I needed to record audio while I was on the go. I tried some Apps from the Store, but I couldn't find any that was able to record while the screen was locked.
I can't walk with my phone in my hand and I have to lock it before putting it back in my pocket in order to prevent accidental actions on the screen.
Also, I couldn't find an App that can record while it's in background.
In this answer I read that Windows 10 mobile will include a minimal App to record audio, I tried to search online for more information, but I can't find any details about the ability to record in background or with the screen locked.