[8bitsrule]

In the US here was a decades-long period when you could buy a set of books for next-to-nothing (from Audel; most are now public domain) that would fill you in on most details of most trades. You (along with friends and relatives) could do the parts you understood and farm out the rest.

My dad (Navy electrician) built his own house with help from a Navy friend (carpenter). It sold a half-century later for 5 times what it cost him. The stucco exterior (whoever did it) lasted with zero fails in a climate that varied from -30F to +90F.