Is that the car's original starter that your mechanic took out? If so, he should just replace the pitted contacts while it's apart--a few minutes work and a coupla' dollars in parts and you're just fine. Those OEM Denso starters are pretty rugged.

You know thats what my mechanic said. He wanted to know where i got that crappy aftermarket starter (Advance Auto Parts) and he said look for a Denso. He didn't seem to think contacts were readily available. He especially couldn't find them for my aftermarket one. He filed them down for me and then said any more problems go for a new starter and DO check the contacts first prior to installation.

Try jumping power straight to the starter's small wire, the one that brings power in from the key switch. Just get a light wire and run it from the battery to the starter and flick it on the small terminal next time there is the no start problem. If that fixes it then you are getting an accumulated voltage drop somewhere(or probably several places) between the battery and the starter, which is fairly common on lots of makes and models. If that's our problem then the cheapest, simple, permanant cure is to fit a relay right near the starter, taking power straight from the fuse box and into the starter when you energise the relay with the key switch wire. It's an industry standard remedy for difficult starting under those conditions in old cars.