92 legacy problems

very new here, but need help desperately, I have a 92 subaru and it or something in it has been killing my alternators, I have gone through 5 in a year, everything that can or could be tested has, but I have a strange feeling I think I know what is is, but no way to know how to fix it....here's my bright idea I think that either my running lights or possibly my headlights are staying on after the key is turned off .. any suggestions

I had the same problem, however I only burned up two. The reason I burned up the second one is the battery. When replacing the alternator your battery has to be COMPLETELY charged. If it is not, it will burn up your brand spankin new alternator. So, take both the battery and the alternator out at the same time, get the new alternator, install it, then put your new battery, or a COMPLETELY charged GOOD battery. After I did that, I had no problems. Remeber, your battery has to be able to hold a charge.
-Danny