There are some shows you watch once, and that's all you need. Especially in this age of binging several series a year, you may not need to go back to old shows the way you might have used to. On the other hand, some shows still deserve it.
Science fiction in general tends to lean toward this sort of re-watchability for a few reasons. Part of it is that due to the settings, it's more escapist than other TV shows may be.
It's also that the big ideas science fiction leans toward might influence creators, which means that several steps forward in television overall got their start with sci-fi shows.
Here are some of the best sci-fi TV shows throughout television history that are still worth rewatching today.
9. Eureka (2006–2012)
The Syfy Channel (formerly known as the Sci-Fi channel) isn't exactly known for the quality of its original content, but some of its original series are surprising gems.
My favorite of those is Eureka, which follows the sheriff of a small town where most of the residents happen to be geniuses who work at a facility that frequently puts the town in danger.
This isn't mind-blowing stuff, but if you're looking for something to watch to let your brain take it easy, you can do a lot worse. Halfway through the series, it gets a reset of sort, which makes rewatching old episodes fun to see how things changed.
8. Mystery Science Theater 3000 (1988–1999)
While it's unlike most of the other shows on this list, Mystery Science Theater 3000 might be the easiest show to watch over and over on this list. Why?
Because the format of the show: A man trapped in space with his robot companions is forced to watch bad movies, which they deal with by making fun of them.
Each episode shows a full-length movie, complete with interstitial sketches that hearken back to the horror hosts of old.
I don't personally care much for the recent episodes, which are available on Netflix, but you can stream older episodes for free on Pluto TV or the Shout Factory website.
7. The X-Files (1993–2002)
You probably won't find many fans of The X-Files who unconditionally love every single episode, even if you cut out the later seasons. That in and of itself is part of what makes this show worth watching over.
You've probably got favorites, and those are what you'll rewatch first. Then you can start revisiting episodes you don't remember or didn't like much the first time. If you're anything like me, you'll find yourself coming away with new favorites.
6. Star Trek: Deep Space Nine (1993–1999)
The entire philosophy of the first two Star Trek series was "to boldly go where no man has gone before."
With that precedent set, making the setting of the third series a space station which, by definition, doesn't go anywhere, didn't go over with fans well at first.
Because its stationary nature, Star Trek: Deep Space Nine allowed both its story and characters more room to breathe. This took a while to develop, but by later seasons it worked well.
Watching this over again to see how characters and relationships change is absolutely worthwhile.
5. Futurama (1999–2013)
Yes, Futurama is an animated sitcom in the same vein as its creator's other hit show, The Simpsons. It also happens to fit in some relatively bit science fiction ideas. These are usually used as a platform for even more jokes, and that's part of the fun.
Futurama is all over, which makes it easy to rewatch. It's also a sort of TV comfort food thanks to the humor, which makes it deserving of a rewatch if you've had a tough week.
4. The Twilight Zone (1959–1964)
If you're reading this and you haven't seen The Twilight Zone, you're doing yourself a disservice. You won't love every episode (few people do), but the show offers so many different types of stories you're bound to like one of them.
Even if you've seen The Twilight Zone before, it's worth revisiting your favorite episodes again and again. If you've been on a Black Mirror kick, go back to the series that so heavily influenced it, and you'll be surprised at how well certain episodes hold up.
3. Battlestar Galactica (2004–2009)
Despite sharing its name and setting with the campy older series of the same name, Battlestar Galactica picked up where Babylon 5 and Firefly left off.
The serialized nature of the story was heavily influenced by the former, while the handheld-style camera was highly reminiscent of the latter.
No matter how you feel about the show's controversial ending, the road until that point was as gripping as sci-fi TV gets. The show is worth re-watching for that reason alone.
2. Babylon 5 (1993–1998)
Babylon 5 might have an (undeserved) reputation as a Star Trek knock-off, but it did many things that hadn't been done on TV before.
For example, it was one long story, rather than the episodic nature of most TV until that point. This is common now but wasn't back then.
This allowed for storytelling techniques like hinting at events that would happen much later in the series. You only really notice this when watching the show for the second or third time, but it's good enough that it's totally worth it.
1. Firefly (2002–2003)
I had to put Firefly on this list first because the series' fans might have rioted otherwise.
Like many shows on this list, this show influenced many shows that came after it, which is part of the reason it's worth re-watching.
Another is that despite the series' linear nature, Fox aired the episodes out of order during the show's initial run, so if you only saw it when it was new, the story wasn't as coherent as it could have been.