The ceiling fan lights in our house switch off on their own so that when we go turn them on we have to pull the switch on the fan often. Unfortunately it is not just one light or I'd know something is wrong with that one fan, but it is all of them. Some of them are old, some of them are new, but have been installed the whole time we have lived in the house. Any ideas on what is causing this?

Are these ceiling fan/light remotely controlled? If you don't use a remote, pull a canopy to see if there is a remote control receiver installed by some one else.

No, unfortunately none of them are able to be controlled by remote.