You only need one.
Some people really enjoy small towns, while others love big cities.
Some like hot climates, others like four season climates. If you want to live in a small town, in a very scenic part of the world, the chances are there will be a lot of other people who want the same thing. That means that good jobs will experience very little turnover which means promotions are few and far between. Suppose you love Vail, Colorado. A beautiful four season resort area, but also an area that is very expensive.