I wish I had followed common "good" practice procedures after I got the car. The drive train obsession really affected the rest. (eg. the dry rotted front windshield gasket - which I only changed recently because I forgot to close the hood correctly and it flew into the windshield.)

btw, on that note - If anyone has a W123 with a dry rotted front windshield gasket, there is a good chance that water and debris carried by water will collect near the hinge+body attachment points. The one on my passenger side is rotted and rusted from the leaky gasket and battery related corrosion. Now the hinge isnt attached to the body anymore - the hole where the hinge attaches is no longer a circle. Point is, change your windshield gasket if its dry rotted/cracked. clean out the space where the hinges attach to the chassis/water drain channels. Treat battery tray and surrounding area for corrosion. Avoid calamity.

I am guessing the only proper repair would be to rust treat the whole area, weld a new piece of metal over the hole, drill a new hole thats the right size and re-attached the hinge....right?