Special Effects Evolution

The inevitable fact that, as franchises go on, they will be given a special effects (very often, CGI) upgrade to compete with the times. Justified in the fact that many of today's sequels are of series from the 1980s or 1990s, where then-new CGI was often ditched in favor of actual explosions and stunts, and CGI is much safer (and cheaper) than, say, blowing up an entire office building. Often results in They Changed It, Now It Sucks.

Anime

 * The Pokémon series continuing today has changed A LOT since the first episode from 1997. The movements of the characters are much more fluid, there's more computer-generated effects (especially the Pokémon's attacks which were originally drawn with the same animation), and the environments are much more colorful and vivid. For its fourteenth opening sequence, it was fully CG, while initially the show didn't even use digital ink and paint.
 * This was one of the actual driving forces of the Neon Genesis Evangelion Rebuild project. It was at its most striking in the first movie, which had a lot of redone original footage.

Film

 * The first Terminator film was just a modestly budgeted film, albeit one with a rather convincing (if not in movement) T-800 "skeleton". Then came along Terminator 2: Judgement Day, which had one of the more famous early uses of CGI involving seamless liquid metal effects of the T-1000.
 * While it did use CGI, the majority of the effects in T2 were done like the first, using stuns and animatronics. The difference was that T2 could afford better ones...
 * Indiana Jones and the Kingdom of the Crystal Skull, made 19 years after The Last Crusade had a lot more CGI used in its action sequences.
 * The James Bond series makes pretty good viewing to see how special effects have come along from 1962 to 2008. Although Casino Royale has actually cut back on CGI.
 * The Star Wars prequels and the re-mastered originals in comparison to the films from The Seventies and The Eighties. So... much Scenery Porn. (Though that is not always the case)
 * Ditto for Star Trek, which has been in near-constant production with films and TV series since the 1970s.
 * The Remastered Original Series in particular.
 * The 2009 film, to, well, anything else.
 * Star Trek: The Next Generation was converted to HD using the original film, requiring the replacement of the SD format special effects.
 * For the first three Die Hard movies, they all depended on actual explosions (with the exception of one scene in the first movie), miniatures and live ammunition. It's stated that the directors favored the real thing over the then-new CGI. Then Live Free or Die Hard had its oil refinery explosion, the F-35 shredding a highway to bits and CGI cars flipping out.
 * Commented on in Death Proof, where Stuntman Mike bemoans the fact that CGI has put stuntmen like him out of work. It's then fully averted in the final act, which features an epic car chase without a single bit of computer imaging.
 * The shift from a simple quad bike to a hovering vehicle as the Mule between Firefly and Serenity. Word of God states that the original intention was something similar for the TV show in the first place, but budget constraints wouldn't allow it.
 * Also partially explained, in-story, with the original Mule being destroyed in the episode War Stories, and the fancy new one being bought with the proceeds from the sale of the Lassiter.
 * The Godzilla series has been going on for over fifty years, and started with men is rubber suits smashing miniature cities to men in rubber suits smashing miniature cities done BETTER!
 * Tron: Legacy, looks much darker and slicker than Tron. The special effects are also much improved, albeit in a much darker setting. This is especially notable since the first Tron film was one of the first major films of its time to use extensive computer graphics. This can also be justified since Tron takes place in a video game world where it must have been upgraded into a newer setting.
 * Clash of the Titans: The newer version uses computer animation as replacements for the stop-motion effects of the 1981 version.
 * The Harry Potter movies started in 2001, so they used plenty of CGI from the start. However, the quantity and quality of the CGI increases with each film. It's telling that Jim Henson's Creature Shop only worked on the first Potter film while ILM worked on every film in the series.
 * In the first film, the floating candles in the Great Hall were done with wires. In fact, after Quirrell announces the troll in the dungeon, there's a close-up of McGonagall in which you can plainly see the wires which the candles are suspended from. An accident with a falling candle prompted them to make the switch to CGI candles for safety reasons.
 * For the first six films, the Hogwarts exterior was a large model built at 1/24th scale. For Deathly Hallows Part 2, they switched to a CGI version of Hogwarts in order to properly create the Battle of Hogwarts.

Live Action TV

 * Doctor Who is made of this trope. A lot of fans found it very jarring when the new series premiered and the spaceships and aliens actually looked like spaceships and aliens, and none of the props were made out of egg cartons and bubble wrap any more.
 * Happened quite a few times in the classic series as well. Particularly noticeable in the last four seasons, which featured a large advance in effects from the previous couple of seasons (a lot of which is still convincing today) and some early CGI. The bump may have been even more noticeable had the budget not been slashed following the 18-month hiatus.
 * It happened more times than that as well - the production team was often able to experiment with some fairly early stuff, but tended to overuse it. What seems now to be a Special Effects Failure was occasionally a Special Effects Evolution at the time, such as the massive use of unnecessary CSO during the early seventies.
 * The new series has a subtle, but visible evolution continually across the Ninth, Tenth and Eleventh Doctor's eras.
 * Star Trek, as mentioned above.
 * Babylon 5 suffers from this a lot.
 * The effects of Walking with Dinosaurs and its sequels have gone through a spectacular evolution beginning from 1999 to 2005. While very good for their time, the effects in the original series have aged quite a bit, and the closeups of the CGI dinosaurs looked particularly odd, which is why the bulk of these closeup shots were realized using animatronics. The computer graphics of the series had advanced so much by the time Walking with Monsters was released, that even CGI closeups looked magnificently lifelike.
 * Tokusatsu is an obvious example, given that the genre as such (primarily Super Sentai and the Kamen Rider franchise) have been around since the 1970s. Of course, evolution can be found on the small scale too: compare the transformation effects in 2000's Kamen Rider Kuuga to the giant monster versus Cool Train battles in 2007's Kamen Rider Den-O.
 * It's especially noticeable during a Reunion Show, when you get to see past characters do their favorite attacks with today's technology. When powers from the 70s or 80s show up in Kamen Rider Decade and Kaizoku Sentai Gokaiger, your jaw will drop.
 * Speaking of new looks for the same tricks, there's a world of difference between mecha and vehicle action between now and the old days. Used to be, heroes' vehicles vs. enemy air force would be the same three or four swooping movements on either side put together different ways. Villain air forces then largely disappeared for ages. Then the moth-vehicles in Go-Onger arrive. Of course, it happened a lot faster for American fans, where the special effects were a bit spiffier. The three-or-four-motion plane fights in VR Troopers and Big Bad Beetleborgs give way to Star Wars class dogfighting in Power Rangers in Space.

Video Games

 * Extremely noticeable in the Duke Nukem series.

Western Animation

 * Parodied in the Freakazoid! episode "The Curse of Invisibo". One moment, the invisible ancient Egyptian is represented by very-obvious wires holding up the magical staff. After an interruption from the narrator, we see the staff floating "on its own" and glowing.
 * Scooby-Doo.
 * In the DCAU, the use of conspicuous CGI backgrounds and vehicles (particularly in the animated films) has continued, but is done much better. Compare the Batwing in Batman and Mister Freeze Sub Zero to the Batwing in Batman: Under the Red Hood.