I have noticed that a lot of my lap siding boards have a small (1/16
to 1/8) crevice where the boards lap over one another -- that is where
the thin top edge of the beveled siding (3/16?)goes under the the
thick (3/4?) bottom edge of the next upper board.

I am painting the boards. Should I caulk all of these crevices?

(Boards have been up and sun&weather-exposed for 23 years.)

Thanks,

FACE