During locals yesterday, we had an interesting mini-conversation about the age-old Magic vs YGO issue, with the majority of it being about the issue of set rotation. For those unaware, set rotation is when a certain number of sets become unplayable after new sets are introduced. For example in Magic, you'll generally have 2 "blocks" (3 sets per block) and a core set (which comes out every year) that are "Standard" legal. Standard is the equivalent to YGO's Advanced. As a new block is introduced, the oldest block will be "rotated out" so the card pool is ever-changing. Obviously we don't have this in Yugioh, but we do have a banned list that dictates what we run/don't run, moreso than Magic's.
People have very different opinions on set rotation, with some making assumptions about it when they actually don't know all the facts behind it. Many people who haven't played Magic believe that once a card is rotated out, it'll never be used again and it basically becomes garbage. Well this isn't necessarily true on two different accounts: 1) reprints do happen and 2) Magic supports multiple formats.
In terms of reprints in Magic, it's not exactly the same as it is in Yugioh. The purpose of reprints in Magic, generally, is to allow the particular card to be legal for Standard play. In Yugioh it's an issue of accessibility. Almost every Magic set has a reprint of some kind, some of them being simple commons/cheap cards (Naturalize, Oblivion Ring), while others are old Rares that haven't seen play in varying lengths of time. When I saw that Vampire Nocturnis was coming back, I let out an "ohh snap" since I ran Vampires as a cheap deck back then (and yes I did fuck up some evenings). Furthermore Magic has a yearly Core set where you find a lot of reprints of various commons all the way to Mythics. These reprints dictate what will or won't be legal for play, hey sounds a lot like our banned list. Something that a lot of people also don't realize is that you're allowed to play with an older version of a card if it was reprinted in a newer set. For example if you have a Birds of Paradise from Ravnica (a 7 year old set), you don't have to get the newest printing of it from M12 to play it. This makes it so you don't have to keep buying new cards, at least the ones that get reprinted. Yearly reprints such as these also help keep costs of bomb rares down, at least to a certain extent. In general, Magic cards have a shelf life of 2 years for Standard-legal play.
When you look at Yugioh's formats, it basically boils down to Advanced, Traditional, and I suppose Pegasus league. Traditional is basically unsupported on all fronts, and I have yet to see a Pegasus league tournament go down. In general, Advanced is the only truly supported format in Yugioh. When's the last time you've read coverage of a Traditional format YCS? Or a Pegasus league regional? Oh yea, never. Magic, however, has always had multiple formats that are supported on the Grand Prix and Pro Tour (and qualifier) level. You have Standard, Block Constructed, Sealed, Draft, Modern, Legacy, I don't even know what else. Their Sealed and Booster formats have always been popular, and the measure of a pro's skill is never completely dependent on their Standard deck alone. A true pro in Magic has to be capable at these other formats as well, otherwise they have to be choosey with which events to attend or just scrub out. As for using older cards, Magic has a format called Modern (called Extended in my day) which allows for even more blocks (several years' worth) to be legal for play. Who knows, your local may not have tournaments that support this format and all, but they do hold bigger events for these formats, which is a lot more than what Yugioh's doing.
So what are the up-sides and down-sides to set rotation? Naturally, having to buy new cards to be able to play the most popular format, Standard, is probably the biggest down-side. This alone has made me quit Magic several times, because rotation was something that was always on the back of my mind and gave me that sense of "oh no I have to get rid of this card before it goes down in value" all the time. I didn't want to always have that feeling and it's something that one shouldn't just ignore. If you play at one period of time, take an extended break and decide to come back, well chances are 98% of your cards aren't going to be legal besides the basic lands unless your whole deck was made from a Core set. If you want to play in Standard, you'll basically always have to keep obtaining new cards. Compare this to YGO, where I've seen a few instances of people coming back, making a few slight revisions to cater to the list at the time, and at least their deck is legal for play and can enter the tournament.
An up-side to set rotation, in my opinion, is that it keeps the game more fresh and broke cards/combos eventually find their way out. The game will always have color-based decks that will see play like White Weenie, Mono-Red, Red/Green, Blue/Black, Blue/White, etc, so in a sense it may not seem like the game is fresh at all, but it's not like in Yugioh where half to 3/4 of the cards in your deck are just staples that have always been around to some extent or another.
What a lot of people don't understand, is that Yugioh basically does have a form of set rotation that is enforced by new sets coming out and via the banned list. Sure, you can run that Soul Control Monarch deck that you've been playing since 2007, but is that going to be competitive enough to handle all the new cards and mechanics that have come out? In most instances, no. To play the broke decks of today like Dino Rabbit, Inzektor, Chaos Dragon, etc, you need to have the new cards from the newer sets to be considered competitive (even though, yes, Chaos Dragon is cheap). Are any competitive decks that were played 4 years ago competitive today? I can't think of any. What happened to decks like Blackwings, Infernity, and X-Sabers? How many cards from the sets which those decks came from are played now? Present to a certain extent, sure, but between the list and new sets, they're basically phased out. In this way, Yugioh does essentially rotate sets out to where players need new cards to stay competitive. In both games, you basically have to buy new cards to play competitively. The only difference is that in order to play Standard Magic at all, you have to, whereas in Advanced Yugioh you don't necessarily.
When I was younger I used to always wish Yugioh had set rotation, but as I got older it became more obvious to me that we basically already do. I always feel like I'm having to pick up new cards, but thankfully I know my staples are safe for the most part. Sure they may ban random staple X and bring staple Y back, then flip-flop a year later, etc, but it's never like "well all this crap's useless now." That just happens to decks in general, but hey that's just how Konami ensures their cashflow. On the surface it doesn't seem like there is set rotation at all, and a lot of players find solace in that; there's no page on their site that has a list of what sets are currently legal for play, so we basically have "freedom" to run whatever we want. However the power level of new cards, the ban list, and the drive to play competitive decks makes it unattractive to actually "run what we want."