To give a little background, we've been replacing the alternator on this car (1995er) around every 2 years. The dealership's service department has been unable (or claims to have been unable) to find any reason this happens.
More currently, I'm having trouble starting then temperatures reach below 35 degrees Fahrenheit. The engine will start, but it starts very slowly, and typically takes a couple of tries. Are these two items related, perhaps?

IF your battery isnt fully charged it will start slowly.
Over time this will wear out the alternator faster because it's working to recharge the battery more then normal.
Has the battery been replaced also ??

But other things can effect the starting efficiency.
Plus, wires (you didnt mention engine size), impurities in your fuel, small vacum leaks, or something in your emissions system isnt working properly.

hope that helps and Welcome to AF.