Why would it be useful to display the volume and never update the value?
I'm suggesting 5 seconds interval as not to increase the refresh rate of the default conf (I use 1 second, myself).
Update volume meter more than once
The block is updated on mouse click/scroll. It seems this is the primary way to change the volume and hence there is no need to have it periodically update the volume for no reason. If you want to change the volume in another way (besides with the mouse), e.g. by script called from a bindsym in your i3 config, just append pkill -RTMIN+10 i3blocks to the end of the command. This is what is meant by signal=10 in the config.
pkill -RTMIN+10 i3blocks
Either way it's very simple for the end user to just change the line to interval=5 or whatever. No need for that to be the default. I put mine to a much higher value, 120, so that it updates eventually. My keyboard volume keys go thru the volume demon, and there is also the automatic change when headphones are plugged in.
Maybe a line in the documentation about this would be more appropriate?
I wasn't aware of the mouse support in that block, all I used was the media buttons. I'll add the signal to its bindings -- maybe it could be used as an example of passing signals to blocks, raising the awareness of the feature.
@barraponto a signal example (in fact, specifically for updating a volume blocklet) is the very first example on https://github.com/vivien/i3blocks. Perhaps you just missed the example? Or maybe it was not clear from this page how to use signals? Or are you suggesting that we add more elaborate documentation about common places to call pkill -RTMIN+1 i3blocks, e.g. inside a script, inside a bindsym in your i3 config, etc.?
pkill -RTMIN+1 i3blocks
Uh, yeah. I kind of ignored that comment in the configuration.
If I see a way to improve it, I'll send it as a PR.