因人而异 – yin1ren2er2yi4
Literal meaning of each character = because – people – and/yet/but – different
This is a fairly self explanatory idiom when you read the meaning of each character. It basically means “everybody is different”, “differ from person to person” or “vary with each individual”
I first came across this idiom when talking about language learning and comparing languages with a taxi driver. I gave my opinion about Chinese being easy and French being hard and I also said that it was only my opinion and someone else may feel differently. I also comparing my learning Chinese faster than french and so on and at some point in the conversation he said this idiom.
So I now use it when talking about language learning to say that some people learn faster than others. It isn’t to say that anyone is a better person than anyone else, it’s just that they are “different”. However I am pretty sure that it can be used to other situations when talking about peoples individual abilities or maybe even tastes etc.