Nothing I do makes any difference anyway, so why bother?

我做什么反正都不能改变什么，那何必费劲？

金山词霸

Why bother turning legit and tying the knot?

何必费心走正道、结为夫妻呢？

金山词霸

Why waste energy obsessing over memories of him?

何必浪费精力沉迷于对他的回忆呢？

金山词霸

Why dwell on those intricate legal specifics?

何必纠结于那些复杂的法律细则呢？

金山词霸

Why do you burden yourself with your sister's dog?

你何必自找麻烦为你姐姐的狗所累 呢 ?

《简明英汉词典》

Why should you work so hard for these people?

你何必替这种人卖力?

《现代汉英综合大词典》

We are all good friends ; why stand on ceremony?

都是自己人, 何必客气 呢 ?

《现代汉英综合大词典》

Never mind such trifles.

区区小事,何必介意.

《现代汉英综合大词典》

I was only joking. Why take It'so seriously?

开个玩笑嘛, 何必当真 呢 ?

《现代汉英综合大词典》

Why should you be so suspicious?

你何必多疑?

《现代汉英综合大词典》

There is no need to go so early.

何必去那么早.

《现代汉英综合大词典》

Why take the trouble to do that?

何必多此一举?

《现代汉英综合大词典》

Why all this hurry?

何必匆忙乃尔?

《现代汉英综合大词典》

Why so much fuss?

何必嘞?

《现代汉英综合大词典》

Why must you go to this expense?

何必这么破费?

《现代汉英综合大词典》