I used to open up Macs all the time, and not just the desktops. The PowerBook G4 aluminum 12" was a really hard one to work with – before the unibody aluminum laptops, so it had some internal framing pieces and a zillion tiny screws that were easy to lose and hard to keep organized. I swapped out the internal HDs on a couple of those a few times.
The most recent Macs I’ve opened up have been a 2008 MBP that I installed an SSD in place of the HD in, and one of my sons’ Intel MBP – I think it was a 2015 13" Intel MBP, to swap out the SSD for a bigger one.
I did a few DIY iPod repairs – the old clickwheel models. I think I replaced the HD in an iPod Photo, and the battery. More than once.
I’m pretty sure I opened up an iPhone for a DIY repair once, but I don’t remember what I did. I just know I have the prying tools and suction cup to remove the screen. The suction cup wouldn’t have been used for the iPod.
But I got tired of DIY upgrades and learned to embrace Apple’s buy-a-new-machine model. It’s partly why I keep Macs so long. Use them long enough and run them into the ground so that a simple HD/SSD upgrade starts feeling like putting duct tape over a leak in an old tire – or the inner tube, back when tires had inner tubes. I also found I quickly got over that “It’s a whole new machine” feeling I used to get when upgrading internal storage.
That said, I did buy an iFixit SSD upgrade kit for my 2019 27" Retina Intel iMac. I wanted to go from 1 TB to 2 TB on the SSD, and after the PBG4, not much really frightens me in terms of DIY upgrades. For now, I’m not switching to a new Apple Silicon iMac because, frankly, the big screen is why I got the 27" iMac in the first place, so I’m holding out. The programs I use are still Intel compatible.
The upgrade kit has been sitting on a shelf for months, though. I just don’t have the time, and I have ~100 GB space on the internal SSD, so there’s no immediate need to upgrade it. Some day, either I’ll find the time, or Apple will roll out a big screen Apple Silicon iMac.
-awlabrador