The other week I was called to a home. My customer had flickering down lights along with weak glowing globes. It was obvious there was an issue. Once I pulled the lights down it was quite easily found, as the transformers had melted and nearly caught fire!
This home was only built 5 years ago. So no matter how old your home is, if you are noticing anything unusual about your lighting please don't hesitate to get them checked. You just never know what's happening "behind closed doors" or in this instance "behind closed manholes".