How often do you re-acquire dark and bias frames?

[Andy Resnick]

Semi-random question: I generated dark and bias master frames (and from those, bad pixel maps) about a year ago. I'm sure my camera sensor has degraded over time.. b/c entropy... and so I'm wondering if it's worthwhile to create a new set. How often do you 'update' your dark and bias master frames?

 

[Drakkith]

Perhaps a few times a year when I'm regularly shooting. I have a cooled CCD camera, so making a new set of dark and bias frames is trivial. I just set my camera up inside during the day and let it go to town taking as many exposures as I want.