I moved into an apartment maybe a year ago, and noticed many lightbulbs were out. When I went to unscrew them, they simply broke off (not shattered) in my hand. It was like someone had scored the glass right where it connects to the metal. In addition, there was a significant buildup of corrosion along the inside of the metal part (I don't have any pictures of how they look, but I'll try to add one the next time this happens).
I thought that was pretty weird, but I finished replacing them anyway (the metal parts remained stuck in the fixture so I had to use a pair of pliers to unscrew them). Ever since, another bulb breaks in the same way every month or so. This happens in multiple rooms, so I don't think it's one incorrectly wired fixture. I've also tried 60W and 75W lightbulbs (just your everyday incandescent bulbs), but that doesn't seem to matter.
Why might my lightbulbs be breaking in this way? Is there anything I can to stop it?
I have a theory that my lightbulbs aren't the proper wattage for my fixtures, and the excess current is causing the corrosion, which in turn destroys the connection between the metal and the glass, but I don't know much about lightbulbs. If my theory is right, is there a way to determine which watt bulb to use?