As a matter of principle I've always tried to run FreeBSD
systems in self-hosting mode, installing from a binary image
and then rebuilding world, ports and kernel from sources.
Admittedly, the practical benefits are minimal, but the
philosophical satisfaction is worth it, for me.

On a Pi, that presents increasing challenges. FreeBSD's
footprint has grown steadily, both in disk and memory
requirements. Pi2 and Pi3, limited to 1GB of RAM, have
real trouble compiling llvm. The only remedy is to use
-j2 or -j3 to limit memory pressure and make sure that
hardware swap in available.  An 8GB Pi4 has no trouble.

In ports, the norm now is to use tools like poudriere to
avoid build conflicts between ports. Simple, CLI-only
ports can often be built using make but GUI ports are
very likely to fail using make because of the incompatible 
libraries used in graphics programming. Perhaps more
daunting, developers rely on poudriere's environmental
consistency to aid debugging build failures. A failed
make in /usr/ports is much harder to debug than a failed
poudriere build and so a report of trouble is far less
prone to attract developer help.

Now (20241119) that armv7 is being phased out the most
reasonable Raspberry Pi to use is the Pi4. With 8GB it's
no problem yet. A Pi3 will work but self-hosting is apt
to be more trouble than it's worth for non-experts. 

There seem to be some subtle problems using small flash 
storage when running buildworld. After prolonged use
microSDs slow down as they have to begin garbage
collection. Further, there have been what appear to
be cases of file corruption that result in build
failures or, worse, corrupted binaries being installed.
This is purely anecdotal, not systematic testing.
Still, I'd now suggest against hosting on other
than conventional mass storage media, meaning
mechanical or SSD hard disks. Thumb drives semed 
to work well to start with, but not long-term.

20250507