SAAB Convertible that often won't start

I have a 2003 Saab 93 convertible that I bought used (had 20,000 miles on it and now has 50,000) and LOVED until last year when I started having problems starting it. It would start fine when I went to work, fine 8 hrs later when I got off work, but then if I’d stopped somewhere briefly and went back out to start it - it wouldn’t start. Nothing - just a “click” when the key is turned. All of the dash lights come on and the engine OK light comes on, but it won’t start. Then if I wait about a half hour and try again, it starts. I had this problem MANY times for about 6 months last fall and winter, took it to two SAAB dealerships/garages and they replaced the alternator, ignition, etc, checked everything and couldn’t find anything else wrong with it, and it still occurred. Then all of a sudden, it was OK for about 6 months. Started all the time. Now, yesterday, the same problem began again. I went out to start it after it has sat for about 2 hrs and it wouldn’t start. Tried again in 20 minutes, nothing. Tried again 30 minutes later and it started!! It is driving me nuts why no one can figure out what is wrong with it!! WHAT SHOULD I DO???

This sounds like a classic case of a failing starter assembly, specifically the contacts that enable the starter motor circuit when the solenoid energizes. Every time the engage they spark a bit and they fry over time. Why they changed all that other stuff for those symptoms is beyond me.