[Edisla]

I had read that stranded was usually used where the wires may be moving around a bit.

My current project appears to have some stranded wire in areas that clearly do not move around.

Why?

It appears to be fairly close to the solid wire used.

Maybe they just used what they had on the factory floor???

[robsradioactive]

As these were hand wired, sometimes it was easier to use stranded...and if that made the ladies work faster, they gave them stranded. Other than that, yeah, whatever they had the most of. Electrically, there is no significant difference for our purposes.
Rob

[morzh]

Wire is wire.
Except some specific applications, as long as your ampacity is satisfied, you could use any.

[Raleigh]

I have noticed in some radios which mostly use solid wire, stranded wire is used where low-amplitude RF signals are connected, such as around the antenna, band switch, and tuning capacitor. I have always figured this was because skin effect would lower the effective resistance of stranded wire at those frequencies.

Sometimes, but not often, braid is used in those locations as well.

[morzh]

If anything, stranded wire is worse at RF than solid. Litz is an entrirely different matter.