に限る (ni kagiru): Nothing better than or limited to
～に限る (ni kagiru)
Meaning
Nothing is better than; be limited to
Formation and usage
Noun, dictionary-form verb, or negative nai-form verb + に限る for the best choice. Noun + に限る can also state a restriction.
Explanation
Present what the speaker considers the best choice in a situation. With a noun, it can also state a restriction in rules or notices. Distinguish the subjective recommendation from the separate meaning of being limited to something.
Examples
疲れた日は、早く寝るに限ります。
On a tiring day, nothing is better than going to bed early.
暑い日には、冷たい麦茶に限ります。
On a hot day, nothing beats cold barley tea.
知らない番号からの電話には、すぐ答えないに限ります。
It is best not to answer calls from unknown numbers immediately.
この割引は、学生に限ります。
This discount is limited to students.
迷ったときは、先生に相談するに限ります。
When in doubt, the best thing is to consult your teacher.
How related patterns differ
に限る can recommend the best option or state a restriction. せいぜい marks an estimated upper limit. べき concerns what should be done, よりほかない means no alternative remains, and わけにはいかない concerns duties or principles.