Originally Posted by DWB

The answer was already posted, running them all on the same circuit, however, you could install motion detector screw in adapters to each of them, so they automatically come on as you walk downstairs.

A few of these:



(you can also get these in sets)

If you don't want to pay an electrician or do it yourself (which would be very easy), these would be a very easy option.

You don't have to put them in every light fixture, but if you strategically place them, it will do the job. I also believe they make other adapters with light sensors so if one light was turned on, it would trigger all the others.