That's the question.

For me, two shows.

Sanford and Son, my all time favorite sitcom. I know just about every last line of any episode. Especially when Fred, Lamont and Rollo were in jail. But other episodes also. I am 55 years old and have seen Sanford and Son since I was a child. The NBC affiliate even showed a rerun of Sanford and Son after cartoons in the 1970's.

The Andy Griffith Show (the black and white episodes). I have seen every one of these episodes from childhood to adulthood countless times. I remember making my father mad (not mad, but annoyed) when I changed the channel of an Andy episode just because I have seen it literally fifty times before.

These I know, especially Sanford word for word. I subscribe to Sanford and Son on Facebook and see episodes online everyday.

A bonus, the Mary Tyler Moore show. I have see this show so many times, again from childhood, I know the story. But I still watch it over and over again.

It's funny when there's a pause and you can spout the line before the actor does. It's like we have those scripts imprinted in our brains.

There's a lot of shows that I've been watching for decades, although I don't think there are any where I watch literally every episode (Barney Miller may come closest). I enjoy now trying to figure out the relationships between shows - which ones are structured the same, what characters are similar, which episodes are adapted from an episode of some other show.

Waltons, some of the Brady Bunch. A few lines from LHOTP

There are a few series I know exactly what will be said and what will happen in any episode if I'm watching it, but for no show can I go "off book", as they say in the theater world.

I have several where I can pretty much quote every line but the only one I watch regularly now is Star Trek on Heroes & Icons network because the time is good (nightly at 8:00PM) and they don't constantly flash ads on the screen during the show or cut scenes for more commercials.

Three's Company and Three's a Crowd of the many sitcoms I would watch these two I would have VHS tapes of many episodes recorded and watch them over and over especially when nothing good was on TV.

I guess you can include the Three Stooges even though they were originally shown theatrically I discovered them on TV.