〜に限る

1. Origins, structure, and basic meaning

• Structure: Add に限る（にかぎる） to a noun or a verb's dictionary or ない form to recommend it as the best choice.
• Basic usage: 休日は静かな公園を散歩するに限る。 strongly recommends a walk as a good way to spend a day off.

2. Common pitfalls and similar expressions

• The best choice and a restriction
  • 夏は冷たいお茶に限る evaluates cold tea as the best choice. 参加は会員に限る instead restricts participation to members, showing a different use of the same form.
• Recommending not doing something
  • 困ったときは焦らないに限る recommends not panicking as the best course. The expression can follow the ない form to present avoiding an action as the best choice.