It seems to me coils do not die completely all of a sudden. More typically, for
an old coil the coil will fail after the car is warmed up, but then when the car
cools down (an hour or two?), the car will start again. This is based on my own
experience as well as general reading. Old coils are sensitive to temperature.

An ignitor on the other hand will not give a warning, as far as I know and have
seen.

Procedures for checking ignitor and coil:
Go to www.autozone.com , click on "Repair Info," follow the pointers to the
repair guides, put in your car's info as prompted, eventually click on  "Engine
Electrical," "Electronic Ignition," then "Diagnosis and Testing."

Since as Dan said you have to remove the ignitor, if you use a magic marker and
draw a line from left to right as you stand at the front of the car) and across
the distributor housing to its base, then you can re-install the distributor
housing and likely not mess up the timing as long as you re-align the mark you
made with the magic marker.

(Note that the distributor housing has three bolts attaching it to its base. The
bolt holes are designed so the whole distributor housing may be rotated to
adjust the timing.)

With Autozone, two other good sites for info on ignitors are:

http://www.markl.f9.co.uk/howto/electrical/igniter/igniter.htm

http://www.gcw.org.uk/rover/igniter.htm