When you buy a pair of high-quality headphones it does not take a long time for you to get used to the extra sound quality and they begin to just sound like normal headphones to you. You only realise they are good when you try on a worse pair of headphones. Because you become used to them there is not much point having a really high-quality pair because you won't notice. There is a minimum requirement to headphones, you don't want them to be terrible, but I think there is no point buying a pair of headphones that cost any more than $30. It's kind of like a paradox, no matter what you spend on them they will just end up sounding normal.