I think you better go first. - Why?

我认为你应该先讲-为什么？

youdao

You know, new clothes are best, and so are old acquaintances. I think, you'd better go back.

衣不如新，人不如旧，依我看来，你还是回去好些。

《新英汉大辞典》

I think I'd better let you go. I'll talk to you later.

我想我应该让你去忙了，我晚点再打给你。

youdao