Moving on from the Apple's Ecosystem (Desktop Version)
Had enough of Apple's lack of caring about their hardware or the lack of effort on their operating systems? Maybe you are tired of their foray into politics and social justice? If you are a Gab user, you are probably familiar with Apple's very obvious double standard with Gab's submitted iOS app. If any or all of this has turned you off from Apple and want to jump ship, read on.
For Files You Use Or Need Access To Everyday
This section is for the data that you need access to on a day to day basis. Put all this into a storage area that you trust and can access without a hitch, such as an external hard drive or a trusted Cloud service. Examples of this could be Dropbox, MEGA, Tresorit, etc. All of my normal 'working files' or things that I need access to on a regular basis is hosted on a service like this. One thing to mention when it comes to external drives: Make sure that your drive holding your information is formatted properly in order to be read to the destination operating system. Whatever you end up deciding, it's also not a bad idea in case of catastrophe to have an off-site backup (Crashplan, SpiderOak, BackBlaze, etc.) of the data prepped.
Email, Calendar and Contacts
If you have utilized any of Apple's iCloud services for your contacts or calendar, export and save those files from the cloud service. If you are already using something like GMail or another third party email/calendar/contacts provider like Fastmail, start working on importing everything there and begin the process of merging and pruning that information. This is a pretty painless portion of the switch unless you have a metric ton of email, in which case you'll need to migrate or save/archive for another time.
Export your pictures from iPhoto (File –> Select All –> Export). Depending on what kind of photographer you are, this could be a space killer. Consult where you'll be putting those files and plan accordingly.
Media From iTunes
The media from iTunes is likely going to be the largest group and the biggest pain in the ass. If you have been with iTunes back when they still used DRM on the songs you bought, then you will likely need to get that converted. For music. the easiest method is to find those song files, make a CD of them, then import them into your new system. I'm still doing this myself but was able to move the vast majority of my music over to Linux without a
single problem. However, the TV show and movie files are going to present another problem as you simply can't burn and re-copy. This might be the point where you either abandon the movie/tv show files altogether or spend some money in getting them converted. TunesKit offers software on box the Mac and Windows side that can be used to remove DRM from music, movie and tv show files and more. It's not cheap but I know it'll work.
Start recognizing which applications you will need to find replacements for. For example, when I switched to Linux, 1Password is not available on Linux, so I substituted Lastpass. The data transferred without a hitch and I've had zero problems since (going on nine months now). Think about what problems are most important to you and begin searching out replacements. One place that can help is the website Alternative To. Despite really missing about three third-party applications on the Mac side, I've found replacements for everything I used normally on the Mac over on Linux.
This covers everything I wanted to discuss in getting prepared to move from Apple's ecosystem. I wish you the best of luck in your move.