easy, i started at age 12 1/2 with my uncle. at this time i was learning and at age 13 i had my first snake. a milwaukee hand held snake, similar to the k-39 with chuck. at 18 i started in the union as an apprentice working for a new construction shop. this lasted for 15 years. i was also able to moonlight after hours and weekends.
when i decided i had enough of new construction. i took my contractors test and went to work for myself. so my moonlighting jobs, turned into full time jobs. i was now available during regular hours.
one of the strangest things about moonlighting was the time i got called to high schools principals office

a customers water service had broken and they contacted the school to track me down
now being completely on my own for 10 years, i get all my work from referrals and other plumbing contractors. i do jobs that they don't do. most of them in the specialty field. i keep busy enough to turn jobs away and only travel 500 miles a month.
today i had a new referral from an existing customer. turns out that she is related to the owner of the next job i was going to. but that was not the person who referred me
in the last 6 years that i can look up on the computer, i have worked for over 1100 different people and companies. some of course only 1 time as it was for a 1 time job from another plumber. but the majority are repeat customers. in fact some have used me since i was with my uncle at age 12.
the real issue with the yellow pages here is that the companies are banking on their 1 and 2 page ads to lure in business. all claiming to be available within 1 hour and an up front price. there's a reason they can make it in an hour, they are not busy
my buddy, who some have met has 20 guys in the field. he doesn't advertise and if you don't call first thing in the morning, you don't get same day service.
it works for me and it works for him.
rick.