Being a maker, I'm quite interested in moving towards a practical
solution of a forever computer using readily available parts. Basically
I want a forever computer now! I've spent a few years experimenting
with various hardware form factors and software stacks, mostly based
off of Raspberry Pi (since that's what I find readily available,
current shortage not withstanding), but also looking into simpler
ESP32-based solutions. Here's a short list of things I've tried:

- Tablet form factor ( https://tobykurien.com/rpi_tab ): 7" and 11"
tablets. The 3d-printed 7" form factor has been my favourite to date.
3d-printable frame, easily repairable/upgradable, you can use any
battery solution from a tethered powerbank (my preferred solution) to
built-in 18650/21700 cells. Can be used as a desktop by attaching a USB
or bluetooth keyboard/mouse. Software stack is free and regularly
updated, can even browse modern websites.

- Portable terminal running text-based interface: Basically the 7"
tablet above but with a command-line interface only, and a permamnently
attached keyboard. This makes the software stack more stable and
robust, meaning I should be able to use it for a long time, even if I
don't receive software updates. Uses elinks for browsing, mpv for
YouTube and other videos, framebuffer PDF viewer, etc. Cannot view
modern (app-like) websites. See here for designs for amazing 3d-printed 
retro-terminals: https://uri.cat/projects/modern-retro-terminal/

- For reading, I use an old Kindle. Instead of making an e-Ink device,
I wrote scripts that compile websites/my todo
lists/calendar/weather/etc into MOBI books readable on the Kindle. This
means I can simply plug in the Kindle into my forever computer, run a
daily script, then disconnect and read the offline content (a lot like
Offpunk).

- For audio, a different form factor is needed. I can't be lugging my
forever computer around while listening to a podcast on a daily walk!
So I need a forever audio player. My old MP3 players still work (though
they need transcoding from modern formats), but they have old and weak
non-replacable batteries and none of them remember where I was (in the
middle of a 30 hour book) when I turn them off or change to a different
track. So I built an audiobook player ( 
https://tobykurien.com/post-1662452469/ ) which works great for that
specific purpose. For music and podcast playback, I would've liked a
player that could be loaded with Rockbox ( https://www.rockbox.org/ ),
but ultimately only an Android phone used as an audioplayer can satisfy
all my needs currently (things like +30s to skip ads/skip chapter/skip
track/skip folder, showing a tick next to tracks already listened to,
bookmarks, folder navigation, etc.).

- I bought an ESPlay device as a potential forever gaming+audio player
device ( https://www.makerfabs.com/esplay-micro-v2.html ). Mostly
compatible with Odroid-Go, but interest in these simple platforms seems
to have waned, although I think it makes for a great "forever" platform
due to it's simplicity and affordability. Game emulation works really
well, although the tablet above loaded with RetroPi is even better for
emulated retro games.

- For a collapse/scarcity scenario, I've been playing with ESP32 and
LoRa radios. I find the Meshtastic project quite appealing for this
scenario ( https://meshtastic.org/docs/introduction ) but without
anyone else to communicate with, I loose interest quickly.

My one take-away is that I'd like to be thinking more about various
form factors, rather than just a single "forever computer". I know I'm
using the term "forever" quite loosely here, but my goal currently is
to escape the commercial products with their locked-down software,
cloud-service dependence, and planned obsolesence. I hope at least my
DIY experiments can outlast most of these (aiming for 10+ years of
use). I'm wondering if anyone else has dabbled in DIY solutions towards
forever computers (hardware, software, or design)?