There's rarely anything such as an "obsolete" tutorial. Applications don't typically remove features. So learning even the base features is helpful. And should any app add a feature which results in a better overall process, having the knowledge of how to accomplish something without the latest, greatest, feature can be exceptionally beneficial. Example: There's really nothing in Adobe CC versions which can't be done in CS versions... the only difference is how easily a particular task may be due to additional features in CC.
I agree a great deal with other answers here. Tutorials can be bad at times because they focus on the "whiz-bang" end result and not really the process of getting there. Tutorial authors often seek to show off their knowledge, even if subconsciously. This leads to tutorials using shortcuts without explaining why or providing non-shortcut methods or skipping over some basic knowledge they aren't even aware they are skipping over. There's no focus on understanding what any application is actually doing. After using any app for a period of time, everyone starts to forget the things they do on sheer instinct but are completely unknown to new users.
To be perfectly frank... the best way I know to learn on your own and gain a more proper understanding of an application is via https://www.vtc.com/ -- now it's not free and I realize that can be a hurdle. But if you're serious, simply spending for a single-course is minimal and will ensure you actually get up to speed on a particular application. Years ago I had a friend needing to learn an application - I had no time to teach them. So, I gifted a course to them and they were up and running with the app in only a month or so - and they started with absolutely zero knowledge of the app or anything which may be considered remotely similar. They, quite literally, started from nothing.
I have zero affiliation with VTC. I merely have experience with one of their products and was very impressed with how easy it was to follow and how well it taught the application. I knew the app well and could see the lessons and how they progressed. It was a very fruitful and logical manner.
Barring VTC, quite honestly reading the documentation for an application - while often dry and unexciting - will get you better acquainted with the actual tools and features of an application. For example, going through Adobe's help files for something like "gradients in Illustrator" will by far teach you more than any YT tutorial will.
I would also point out, you need to ensure you are researching applications actually used in the design profession. The only place I've ever heard about "MediaBang" was one or two questions at this site. I've never heard of it used in any professional circles. Now, that's my experience - perhaps it is used more in other parts of the world.
If the gaol is graphic design, you need to probably first get acquainted with Adobe products. While apps such as Gimp, Inkscape, Sketch, etc can be useful, you need to be aware that Adobe has been the primary source of graphic design software for more than 40 years. If the goal is to be employed then you better know Adobe products. If the goal is freelancing, being able to provide Adobe files will only be beneficial. Not having even a basic understanding of Adobe apps in graphic design is almost equivalent to not knowing how to use a pencil.
Merely learning software in order to be a Graphic Designer seems to be a common misconception.
Trying to achieve a career in graphic design by learning various software products is akin to trying to learn how to build a house through the study of hammers, screwdrivers, drills, and wood. Ultimately one does need to know the tools... but the tools themselves have very little to do with any actual design.
Graphic Design is not all about software. There's myriad knowledge which goes into effective design that has nothing to do with any software package.
Learning the tools of the trade is, quite frankly, minimal in the grand scheme of things. Effective design is created by using the tools as an extension or mechanism in order to achieve the overall concept of any design. Tools won't tell you how to solve visual hierarchy issues, where to place elements, what size to make something, color choices, proximity, visual balance, how to be a critical thinker, .... etc.... Being the most knowledgable software user in the world does not, and never will, make anyone an effective or good graphic designer.
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