[Averton (P and C)]

How often do you need to clean your DSLR sensor?
Do you find using your DSLR on a scope gets more dust on the sensor than in use with normal lenses?
Do you wet clean the sensor?
We have found that using our DSLR on a scope the sensor has significant dust on it in a very short time. Is this just because we have the camera not attached to something for longer periods of time or that working in the dark it is easy to get dust on things, lens caps, lenses etc?
Some professional photography sites do talk about cleaning the sensor before any important photo shoot!!
Any thoughts?
Thanks P&C