I don't think it's essential, but I have played with my Herpstat and used a night drop of 2-3 degrees. Rio Bravo Reptiles web page has a good article on using a seasonal gradient for temps.

A lot of it is a natural event in our homes so you may not have to do anything other than let the season or time of day do the work.

If you have no issues and everybody is eating, shedding and feeling good you are doing fine.

I love the Herpstats though. I like to let mine drop a degree or 2 at night, but that's a personal choice I guess.