I don't call regularly but I do maintain my own catalogue of dances which I
transcribe in Word and often subsequently save as PDF. I also have a (very
professional. lol) grocery store produce bag of printouts that I carry
around. I prefer a piece of paper in my hand but have called from my
smartphone as well.
I put the folder of all my contra files in the cloud, most recently
OneDrive. By doing that, the files are accessible on any device with net
access. On my own devices, I can set the folder to be available offline
(i.e. stored on the device) should I not have net access.
Unfortunately, not all cloud products are created equal and functionality
in the same product is sometimes different from platform to platform (e.g.
phone vs laptop), so be watchful.