How often do you tune your herbie overflow?

[mrhasan]

Well I tuned my herbie overflow at the beginning of my new tank (20 days ago). I made a small trickle go down the emergency like many suggested. Yesterday night, I found out that the water level in the overflow went down by around an inch. I thought overflows are suppose to get its flow lowered through the pipe in time (thus increasing the level) but mine seems to do the opposite. Anyway, took me a minute again to get to my desired level again.

So I was wondering, how often does herbie needs to be adjusted? Looking for some experience out there