One of the enduring national myths of the United States is the tale of how the Founders, all men with lives outside politics, created the country, then went on with the rest of their lives. Nothing could be further from the truth. The statement that, for the first 150 years of the country's history, members of Congress came for short stays and then returned home to resume their former careers, is at variance with the facts.
The Founders were full-time politicians who lived, breathed, and ate politics and government. They were career politicians. Had they not, they could not have accomplished what they did. The only term limitation in the American government was that established by George Washington, who declined to run for a third term - to which he would have been overwhelmingly re-elected - and in so doing established a tradition that was not broken until Franklin Roosevelt ran for a third term as President in 1940.
Until the Civil War, the United States government was dominated by men who had first come to Congress in 1812. Henry Clay, who held off the Civil War for more than forty years died in office in 1850; John Quincy Adams ran for the House of Representatives and served for over seventeen years after being President. "Professional politicians" have led us from the first.
Reformers generally want to limit terms to three two-year terms for the House of Representatives and two six-year terms for the Senate. They have attempted to accomplish this state-by-state, generally by direct appeals to the electorate - who generally know nothing about how politics actually works and are easily propagandized by myths such as the one quoted at the beginning of this - or by having the legislature pass instructions to congressional representatives that they must vote for this as a federal law. There have also been movements to have state legislatures call for a Federal constitutional convention to accomplish this.