也许有必要买个新的了。

It may be necessary to buy a new one.

《牛津词典》

我认为有必要买部手机以便联系更方便。

I believe it is necessary to buy a cell phone so that we can contact more easily.

youdao

其实我本没必要买这么多酒，只来了三个人。

I actually needn't have bought so much wine-only three people came.

youdao

Okay. Longer sit down meals are unnecessary because you can just go buy it all of a sudden.

好的,长时间坐着吃饭没有必要,因为你可以随买随吃

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

It's not published yet and so I'm going to put chapters from the book that are in fairly final form, and I think you'll find them easy to read, but you don't have to buy it.

还没有出版,所以我会把,书里基本定稿的章节放在网上,我想你们会发现它很容易读懂,而你们也没有必要去买它

耶鲁公开课 - 生物医学工程探索课程节选