Yup, usually sleep and money, the two things that get in the way of everything.
People ask me sometimes how I balance having a family with my otherwise busy schedule, but honestly that's the easy part. My workshop door is always open, and the kids know there is always an extra chair, a TV with netflix running, and an unlimited supply of snacks, plus they can always make an extra buck here and there helping out. I don't need perfect concentration, I'm happy to have company. If I'm working on pedals when my kids are awake, there is almost always at least one in there with me. Pedals are a big enough part of my life that it's just become a part of the whole family's life.
The tricky part is always balancing sleep with my brain.