Most of my clients do a combination using a contractor for the foundation, sub-floor and the assembly of the framing package. And plumbing and electrical require a special skill set that require a professional be hired for the job whether by the owner or the general contractor. And no one seems to want to tackle drywall, tape and texture.
And then many of my clients love to get involved in the finish work either using a hobby and skill that they already have - or learning new skills.
The following pictures were sent to me by a client building their retirement home and I love how involved they have gotten in truly making this their dream home. (And retirement here is a word I use lightly as I think they have been joyfully 'working' harder than ever!!)