You've been hearing bad things about Spotify's business practises on Tumblr and you want to stop using it, but you just keep coming back to your playlists. Or, you've been trying to start phasing out your phone in favour of your computer, and you've had some measure of success. But, you keep getting hung up on your Spotify playlists. "How am I going to make it through the day without listening to my music?" You don't have to give up your music; but, at the same time, you don't need to use Spotify ever again, either. It's simple, and I'm going to tell you how it's done.
The first method involves a web tool called Spotify Downloader. As all operations are conducted in the browser, you can use any web-capable device, including phones and tablets. The instructions are fairly straightforward: simply provide the service with the link to the individual track, album, or playlist that you want to download, then select "Submit". The service will do some processing, then it will provide you with a ZIP file containing the materials you requested.
Pros. The resulting audio files have metadata and album art assigned automatically. You can also install the service's userscript into your browser script manager (eg. Tampermonkey, Violentmonkey) to add a download button to the Spotify web player, which will do the same thing as the web tool but you won't have to copy links or go to a different website.
Cons. The maximum playlist size is 100 tracks. Also, like any web-based service, its continued operation is contingent upon the affected corporate entity not taking legal action against them.
The second method involves a command-line tool called spotDL. Unlike the Spotify Downloader web service, spotDL is capable of categorising by artist, though podcasts are still not supported.
Pros. There is no theoretical limit to how many songs you can download at a time. You can also have the utility search for a particular song and download it without directing it to a particular link. However, you can only do this by song, not by playlist or album. Also, you can use it to log into your personal spotify account and download all of your playlists in one fell swoop.
Cons. SpotDL has no graphical user interface, you must use the command line. If you're a Linux user, you're probably accustomed to using the terminal, so this won't pose an issue. So far as I can tell, the only specific Linux distro that spotDL is compatible with is Arch. Other distros will need to use Docker. As is the case with most computer programs, the tool was intended for Windows. Finally, spotDL relies upon Youtube to download songs, and Youtube throttles audio quality to 128kbps for all users except Youtube Premium subscribers. 128kbps is lo-fi enough to cause MP3 jangle, which may be a deal-breaker for some. There is an ongoing boycott of Youtube in protest of its use of AI to determine whether you are a minor or not and make "transformative" edits to uploaded videos. Any use of the Google Video CDN is stepping over the picket line.
Finally, there's FreeTube, an ad-free Youtube frontend for Linux, Mac, and Windows PCs. I'd been debating whether to mention this or not, seeing as how determined Google and various national governments are to keeping free and open-source software down these days (and, of course, the AI alterations that Google is making to Youtube videos without creators' consent), but as long as I'm recommending spotDL, I may as well keep FreeTube here.
Pros. Ad-free, tracker-free, AI trainer-free Youtube experience. The FreeTube developers don't monitor your use (because they don't log it), and Youtube can't either because the program accesses the Google Video CDN directly.
Cons. There is an ongoing boycott of Youtube in protest of its use of AI to determine whether you are a minor or not and make "transformative" edits to uploaded videos. Any use of the Google Video CDN is stepping over the picket line. Also, whether you observe the boycott or not, this method is the slowest and most circuitous way to download your Spotify playlists, because it doesn't involve Spotify at all. You will need to download each song one at a time, which just isn't feasible in all use-cases. I would consider FreeTube only as an absolute last resort.
Unfortunately, I can't recommend NewPipe anymore, since Android users are about to get limited out of any apps except what comes from the Play Store. It may still be a viable option for people running old versions of Android or have rooted their phones, but the number of use-cases where I can recommend NewPipe is going to shrink dramatically over the next 2 years.