Among the inquiries we get from people wanting to learn Illustrator or Photoshop, we're sometimes asked, "The software installed at our office is a slightly older version. Can I still use that?"
Software such as Illustrator and Photoshop is currently on the CC version. Before that, it was the CS series.

As someone who works with computers, the "correct" answer might be "you should use the latest version," but personally I answer, "either one is fine."

...That's because someone who has been using Illustrator for a long time might want to ask, "Isn't there a feature for this?" or "I wish this were easier." But if you're at the level of "I'm just starting out" or "I'd like to try making something like this," the CS series is more than capable.

For example, with Microsoft Word and Excel, the latest version is 2016, but 2013/2010 cover the basics just as well. If what you want to do is only available in the newer version, then buying the latest one is your only option, but for the basics there isn't much difference. (If the basics changed frequently, it would be hard to use and quite a nuisance.)

For those who already own an older version, we recommend getting comfortable with the CS version you already have rather than the latest CC—and then moving to CC once you think, "I want to do much more!" or "I want to create work using the most cutting-edge features!"

Also, since 2013, CC has been sold in a form where you download the latest version as it's released. Before that, you purchased the software outright. Back in the CS days, the purchase price was high enough to make you hesitate to buy it as a personal hobby... For example, searching online for the price of Illustrator CS6 gives 58,800 yen. It wasn't a price point that let you casually think, "Maybe I'll give this a try" or "I can't get the hang of it, so I'll quit." Once you bought it, you had to get your money's worth!

With the CC series, however, the software now uses a monthly subscription model.
So you can start casually, skip the subscription during periods when you don't use it, resume payment when you want to start again, and always use the latest version. I also think the barrier to adopting the software has been lowered, even for companies that aren't design firms.
It seems there are now companies that ask someone in-house with a sense for design to create the flyers and ad designs they used to outsource to design firms.

• If you don't own the software at all, go with CC;
• if you already have CS, study with CS;
• and if you want to do even more cutting-edge work or do it professionally, go CS → CC.

That's what we recommend.

I believe I read this in an online column a while back...

Regarding how things shifted from CS to CC: up through CS, a new version of the software was released roughly once every two years. From the developer's standpoint, to get users to buy the latest version, they had to add features every two years that made people think, "I have to upgrade to this!" If the new version's features weren't appealing, users would keep using their expensive software for years on end.
It was about 25 years from the very first release until CC. Features were gradually added over that time, but after 25 years, isn't it tough to keep coming up with appealing new features? So one theory is that they switched to a monthly plan to make it easier for people to buy and thereby increase the number of users—that was the gist of the article.

I don't think that's the only way to look at it, but it's certainly become easier to recommend to people who want to use it as a hobby, and since CC there have been few new features that you absolutely must learn.

I hope more and more people who think "I'm curious" or "Maybe I'll give it a try" will jump in! ♪

As an aside... the current version is CC, and before that was CS. I've been using it since version 5.5, which came before those. Wondering how many years ago 5.5 was, I looked it up: "1994"... 23 years ago (´・ω・`)