My limited experience with a group of exit lights is that they used
special expensive bulbs, but the electric supply place I went to find
replacements suggested some relatively new (at the time) replacements
which had a significantly long life spec. They were (are) neon bulbs as
I remember, and they have lasted many years. Well worth the money.
Exit fixtures have specs on what bulbs are to be used, I think.
Also, as someone stated wrongly about neon bulbs requiring high
voltage, they instead need series R to limit the current. --Phil

nobody wrote:
In wrote:

But in 1978 I wired the 2 bulbs in the each of the EXIT lights in
the church in series.

Congratulations, you probably bypassed a safety feature. If they're
in parallel, if one burns out the other keeps going. In series, if
one goes they're both out, and the exit sign is no longer visible.

--
Phil Munro Dept of Electrical & Computer Engin
Youngstown State University
Youngstown, Ohio 44555