How do you start seriousish side projects?

Hey IH! Quick question.
When you have a new side project in mind, do you usually work on it alone?
Do you find a friend or “cofounder” to work on it with you who has the opposite skill (front end/backend/etc)?

I’m finding it takes a looong time to build things when you’re doing it all yourself. (Ex: mobile app + firestore backend)

Maybe I should spend more time thinking/planning first 😅