By Ken Tucker
Updated July 02, 2009 at 07:42 PM EDT

Tonight, NBC is airing two episodes apiece of 30 Rock and The Office, which got me to thinking: Which of these superlative sitcoms holds up better when you watch them as summer reruns?

I’m not trying to set up some ridiculous which-show-is-better comparison — obviously, each of these sitcoms is first-rate and has unique qualities. But different questions of style and content come into play here. Does The Office, which tends to follow storylines for longer arcs, make for less-engaging rerun drop-in visits, because you have to know the backstories? (For instance, one episode tonight involves Ed Helms’ Andy finding out for the first time that Dwight was intimate with Angela.)

By contrast, any edition of 30 Rock is so chock-full of free-standing one-liners and brilliant, out-of-nowhere non sequiturs, that you can drop into any episode and not have to know too much about what’s gone on previously. Tonight, for example, there’s a rerun about Liz’s first date with Jon Hamm’s character, and Jack wanting so much to bond-in-every-sense with Salma Hayek that he attends a Catholic service with her.

I apply my own Seinfeld rule to sitcom reruns. What I mean by that is, Seinfeld is the one modern sitcom (its predecessor would be The Honeymooners) that for me, no matter what episode or season I drop in on, I want to spend time with those characters — be a part of that comfy world for a half-hour.

Right now, I’m leaning toward The Office as providing that kind of welcoming rerun-world most often. But I could be persuaded that 30 Rock is its own alternate-universe of warm pleasure.

What do you do? When you come across an Office or 30 Rock rerun, which one are you most likely to watch?