expression
to each their own; people differ; everyone is different
A set phrase acknowledging that preferences, opinions, or circumstances vary from person to person. Often used to accept differences without judgment.
趣味は人それぞれだ。
Tastes differ from person to person.
何を大切にするかは人それぞれです。
What people value is different for everyone.
Similar meaning (ten people, ten colors), but 十人十色 emphasizes variety more vividly, while 人それぞれ is a milder, everyday phrase.
Compound of 人 (person) and それぞれ (each, respectively). The phrase is a straightforward combination with no unusual historical derivation.