How often do you...

[ggunn]

Every 6-months in both of my active basses.

Every time I forget to unplug my bass at the end of a session... ;^)

 

[6Steve6Harris6]

It all depends on the preamp, I suppose. But as a general rule, I'd recommend replacing it every four to six months.

 

[bassistgook]

That bass has passive pickups. The EQ is active. I usually change the batteries every 2 months in my basses just to be safe. Remember to unplug your cord when you aren't using your bass to make the batteries last longer.