I can't emphasize this strongly enough: no juniors. Probably for the first 3+ years. They're a disaster, and it's taken my company a year -- with another year or more to go -- to recover.

It's not even necessarily their fault; they just need piles of time and mentorship and direction that you can't afford to give yet. Worse, you'll quite possibly end up firing them when you eventually start reigning them in and they don't like being told how to build things.

Trust me, it's been an extremely painful experience.