I have read that, Settings are centrally important to the novel. They have to be generally motivated, as they are integral to the plot and storyline. Unless you are writing a picaresque it is unwise to have more than three settings.
I have four Settings in my historical fantasy novel.
Many novels have one Setting, where for example the events take place in a city, town or on a boat.
In Wuthering Heights by Emily Bronte, the Settings are Wuthering Heights and Thrushcross Grange, which are four miles apart and separated by the heath which is integral to the plot and storyline.
In my experience of reading and film-watching I found the three setting/location to be perfect in terms of the balance between diversity and coherence...For a good example you can watch episodes of Lost where they usually use two island locations and a flash-back/forward, enriching the plot. Also, another good example in TV is the show Entourage where they constantly change locations