Divers,
CESA is one of the skills I can bet virtually none have practised again after being certified as an Open Water Diver. Some may think that it is a redundant skill to practise since the habit of checking pressure gauge is something that has to be embedded in the habitual pattern of every diver. So running out of air is NOT an option. Especially not so for you and buddy to run out of air together. Be responsible to your buddy and yourself when diving.
However, there are instances when CESA is something that you may need to do...in the case of an attack by predatory marine life for example...or an up-current that forces you up...you will have to know what to do.
Therefore, it is always good to practise ALL your skills, including CESA in the pool when you have nothing to do over the weekends. There are many instructors and DMs in this forum..all of whom, I'm sure, will be glad to assist you in practising these skills.
Dive safe. With practise, you make diving safer.