Definitely. Any more than one and you're setting yourself up to fall. How I've managed to put dual focus into two projects for a while (startup and my main com

Definitely. Any more than one and you're setting yourself up to fall. How I've managed to put dual focus into two projects for a while (startup and my main company) is to focus solely on one for a certain length of time, then switch to the other and give that one 100%. But even that only works so well because a running business has certain day-to-day activities you need to do and can't neglect. So if you're starting your own projects or startup, choose one and give it 100%, otherwise you're not giving any of your ideas the full shot they deserve.