に限る

限る is a verb meaning “To limit”. It has quite a few に expressions:

• に限る – X is best (The options are limited to only one)
• に限らず – Not limited to
• に限って – Only then, Always then.
  
  

に限る

X is definitely the best
Plain form verb + に限る
Noun + に限る

に限る is the most basic of the 限る expressions.
It means that something is the best for a situation. (Literally, limited to X).
This pattern is typically used in combination with a Time.
に限る expresses an opinion.

Examples

• 寒いときは、お風呂に入るに限る – When it’s cold, getting into a (hot) bath is best. 
• 病気の時は休むに限る – When you’re sick, you should definitely rest.
• 夏の夜は冷たいビールに限る – Beers are best for summer nights. (This is said a lot)
  
  

に限らず

Not limited to
Noun + に限らず

If you remember that ず = ないで then you won’t be surprised that に限らず means “not limited to“.
This expression is not typically seen as に限らないで。
Its kind of the same as だけではなく.
This expression likes to pair with も.

Examples

• 今に限らず、昔から厳しい人だ。 – Not just now, has always been a strict person.
• ピアノに限らず、歌うのも上手だ – Not just limited to the piano, she is also good at singing. 
• 学校に限らず、家でも反抗的な態度を持っている – Its not just at school, he has a rebellious attitude at home too.
• 蜂に限らず、色んな虫も育っていている – Not just bees, they’re raising other insects as well. 
  
  

に限って

Only then, Only when…
Noun + に限って

に限って expresses that a statement is limited to a particular Noun.
This can be also used to express exasperation like “Of all days”; particular used with a time.
This may also appear as に限り。

Examples

• 疲れた日に限って忙しくなる – It only gets busy on days I’m tired. 
• オフィスの鍵を忘れた日に限って、他のスタッフも忘れる – Only on days I forget my key, everyone else does too. 
• クレームがある日に限ってマネージャがいないんだ – Only when we have complaints is the manager not there. 
• 最初の10名に限って商品を送り致します – We will give a gift limited to the first 10 people. 
• マネージャに限って、室料を変えることができる – Only managers can change the room rate. 
• この居酒屋は成人に限っている – This bar is limited to adults. (Slightly different usage)
• 1時間に限って、食べ放題だ – For only 1 hour, you can eat as much as you want.