I have found that the work I do is better quality than I can get if I hire it out. (except for really specialized stuff like electron beam welding and other high end work) Not that I do superb work but rather most jobs I've hired out have been mediocre quality for a premium price and like most of you have noted, you have to go behind the workers and clean up their mess and sometimes repair their repair.
At the cost of some jobs as 2Gringos said you can buy the tools and use them again for other projects. Since I can't afford a therapist, I use boat repair as my "therapy". There's something very attractive and soothing about getting lost in thought on a challenging project.
Boat repairs of the "major" category also give you a chance to practice Engineering systems and repairs of all sorts. (it helps to be an Engineer though so you don't over or under Engineer a project or repair)
DIY 'til you Die!
Opportunity is missed by most people because it is dressed in overalls and looks like work.