I had a similar situation and went ahead and replaced pretty much everything so I'd never have to worry about it again; replaced the starter, alternator, start/alt/battery cable, and the ground cable. While I was in there, also replaced the belt, idler pulleys and the tensioner pulley.
Since I DIY'd all of this, the total parts bill was about equal to that of having a shop replace only the starter.
Should be good for another 15 years.
