hi piotr,
I use outlet_float() in an external to output messages. How often is it allowed to send a message in a loop? I didn't find anything about it...
short answer is there isn't - you can go as fast as current blocksize allows, long answer is a bit dependent on what you are trying to do - best practice IMO if you have to update a value regularly is to request a clock from pd, set a sensible default and use this as a tick to send out your floats, I'd also make the delay time settable by the user with some message (i.e. [ refresh $1 ( )
HTH
x