Would you say they are usually short, or long? Are those long all day like dreams possible when your lucid?

I've had them when I was a little kid, but I haven't slept in my back in many years due to "being more likely to have a scary dream" (my mom told me about it, I now wish she didn't). Now I'm back to sleeping on my back, but I'm not having lucid dreams as often as I did as a kid (unknowingly).