I just look at the "seeing" forecast and if it looks decent ('7' for Sydney!) then I'll give it a go!
If, when you plug the camera in, the image is just a blob jumping all over the place, then it's probably not going to be a good night
On the other hand, I've had a couple of nights with Mars where the dark features were readily discernible on screen.
Equipment...capturing...processing. ..it's all part of the fun
