I second what @toruchi is saying.
CSP is pretty good with offering assets you can use for your comics, and they generally show some steps on how to use them. I use assets often for my backgrounds. Granted, I doctor them up so it doesn't look noticeable, but it saves me hours of work.
Galaxy scenes? I slip in space backgrounds, change the hues a bit, use a star/planet brush, and there we go.
Flashbacks? I reuse older panels.
Yes, it helps to practice drawing more and improving your skills. But if there is an easier way to do something, I say do it. Especially if it's going to be a reoccurring theme in your story. Hell, I've gotten to the point where I just started to make my own custom crowd brushes for scenes.