I\'ve always said that successful TV shows are those which are still regularly rerun 10+ years after the last first-run episode on non-niche channels.
That would include:
Seinfeld
Cheers
Friends
I Love Lucy
The Honeymooners
M*A*S*H
As far as current first-run \"successful\" shows with syndicated rerun potential well into the 2030\'s:
Big Bang Theory
2-1/2 Men
The Simpsons
As much as I like \"How I Met Your Mother\", I really think it will be a show that will enjoy some rerun miles for a few years after the CBS finale airs, but will fall off the \"syndicated everywhere\" radar soon after...Just like how Mike & Molly, Rules of Engagement and the stable of CSI shows will/are rise & fall in local TV markets.
I never can understand why hour-long shows aren\'t seen in syndication too much in a Monday-Friday strip, yet the stations will double, triple and quadruple-pump 30-minute shows into the ground, usually into hour-long blocks.