I seem to remember in an early episode Jerry says to Kramer that he (Kramer) hasn't left the building in years.
But of course following plot lines have Kramer going everywhere, even driving alone to LA.
Fans discuss whether Kramer was established as not leaving his apartment building in early episodes, noting apparent contradictions with later plot lines where he travels extensively.
I seem to remember in an early episode Jerry says to Kramer that he (Kramer) hasn't left the building in years.
But of course following plot lines have Kramer going everywhere, even driving alone to LA.
It's in the first episode "The Seinfeld Chronicles".