Particle.variable() overhead?

Firmware
1

How many bytes overhead when you register a variable using particle.variable()?
I guess data usage is minimal if the GET http is only called rarely to retrieve the value?
In this case, it doesn’t matter what the overhead is?

I can hear when my Electron transmits over my speakers. It talks every few minutes when there is a variable exposed. Way more than the 23 minute ping. Am I correct with this observation?

2

If you (or anybody else ;-)) are not requesting the variable the cloud won’t poll it.
So what you hear is either someone nudging your device or it might just be the cell tower.