There is a meme going around the conservative news sites and aggregators that 2016 presidential candidate Bernie Sanders didn't "earn a steady paycheck" before the age of 40. See, for instance:
The origin seems to be this Politico article:
But if his positions are well known, the person, it turns out, is less known. Before Sanders was a U.S. senator, before he was a congressman, before he was mayor of Burlington — before he won one shocking election, then 13 more — he was a radical and an agitator in the ferment of 1960s and '70s Vermont, a tireless campaigner and champion of laborers who didn’t collect his first steady paycheck until he was an elected official pushing 40 years old.
What truth is there to this claim?