Dirty battery cables.

This reminds me of a similar situation with my daughter's '92 Grand Am.
Replaced the starter twice within about a week's time because of the
machine's recurring failure to start.  After the third such incident I got
out the schematics and physically tracked down every last wire in the
starting circuit.  Lo and behold a bare spot on the wire to the solenoid
turned up.

Evidently every time I replaced the starter the wiring harness was being
disturbed enough when the machine was jacked up that for a short time the
bare spot would no longer be in contact with the frame.  The car would start
just fine afterward and I would pat myself on the back for a job well done,
only to be frustrated a few days later after it failed to start once again.
The gist of it is that there had never even been a single starter failure
from the very first incident.  My face is still red.

Your problem may be caused by something totally different, but perhaps you
should take a look at what is being disturbed when you replace the starter.
Also be sure to have the suspect starter checked to confirm that it really
has or has not failed.

where are you getting the starters from?or buy a super battery!1000
crank amps is good for winter.check your battery to ground
connections.big and small.starters require very solid amp carrying
connections.one time i drove to an autozone for paint and came out and
nothing but clicks!!i literally had to replace my positive battery
connector end to get it started!!in the summer!!go figure!!worked fine
up until then!!not one misstart!!