I have permanent standard 40W 48" fluorescent fixtures in the bathroom (1)
and kitchen (3) installed by the builder 14 years ago (I have owned house
for 5 years). Recently, a bulb in the bathroom failed. Until I could
purchase a new bulb, I "borrowed" a bulb from the kitchen to use in the
bathroom. It works just fine.
Meanwhile I bought a two pack of GE kitchen and bath bulbs. I replaced the
missing bulb in the kitchen fixture. There was some flickering at first but
that went away. The next day, the fixture suddenly went out although the
other fluorescent fixtures on the switch stayed on. I replaced the new bulb
with the second new one and still had problems so I put both new ones in. It
worked fine for a few days, then suddenly went out again. When the switch is
turned off overnight, it comes back on again.

Some facts:
The fixture worked fine until I borrowed the bulb.
I have not tried shutting light off for shorter than overnight (It has only
been a few days).
I have had problems with the two new bulbs and with each of the new bulbs
paired with the old bulb.
It is a pain to get to the bulbs so I hate just moving bulbs around for
"fun".
I know the ballast could have suddenly had problems but it seemed so
coincidental.

Any suggestions?

John Pezzano