Not that I really know what I'm talking about, so take my response with a grain of salt.
Mostly from what I've read...
Oil/enamel paints take awhile to dry, so just running thinner/cleaner through the AB between color changes are fine.
Acrylics dry quickly and can plug up your AB. Taking it apart once and
awhile and giving it a thorough cleaning is a good idea. Especially if
you're spraying for an extended period of time.
Like I said, I've read that in a few AB'ing books.
20 years ago when I was doing some occasional AB'ing on auto's, just
running thinner through it was fine when spraying enamels. I would take
it apart and clean it after about an hour (or a few color changes) when
I was spraying lacquer as that paint would tend to "skin" over and
start to plug-up the AB.
On Fridays I'd totally strip down and give a thorough cleaning to
all my spray guns, they only received cleaner through them during the
week no matter what I was spraying.