Poll state node: what's the limit on polling frequency?

the system will allow you to put a number as low as 1 second for polling frequency, but what’s the realistic lower limit? is 1 something that can be done without blowing up the entire system, or is 30 or 60 seconds the more realistic lower limit? or something else entirely?

I believe the question is more, what are you polling.
If it’s local then 1 second is possible/realistic.
If you are polling external source then you will probably be banned.

And what is the use? Are you polling a light state then 1 second is probably not necessary.
If it’s a remote button presses, sure sounds good.

would all be local. use case would be a more realistic way of tracking how long a given door or window has been open or closed…right now i have it set at 60 seconds, but realistically if used as a trigger that could cause an automation to either fire potentially 59 seconds late or not fire at all if the door or window is opened in the gap between when the node is polled vs when the automation fires…