number of indexes for several retrieve

Hi, For an entity that is being retrieved a lot in our application. We want to implement indexes. sometimes we retrieve the objects with name and city. sometimes with only name. sometimes with only city. Should we implement 3 indexes for those 3 cases? (name and city, name, city) Or only 1 with name and city? Or 2 with name, and the other one with city? Hope this is clear, Thanks!