An idiom meaning 'to each their own'—people have a hundred tastes for a hundred people; opinions, preferences, and ways vary from person to person.
旅行の計画は人によって違う。百人百様だから議論が尽きない。
Travel plans differ from person to person. Since everyone has their own preferences, the discussion never ends.
好みは百人百様だから、自分に合う方法を見つければいい。
Since tastes vary, it's fine to find the method that suits you.
面接での答え方も百人百様だ。正解は一つではない。
There are many ways to answer in interviews; there's no single correct response.