When should I use どうやら?


So I learn recently the word `どうやら` and the fact that it comes with `らしい・みたい`.
Until now I have been using only `らしい・みたい`, so my question is why people are
adding `どうやら` at the start? is it neccery?




I think similar word of `どうやら` in English is `apparently`. So if you have some
more information, you can use `どうやら`.

If you heard from someone (without any additional information), you can say

> 彼は風邪をひいたらしい。（He seems to have caught a cold.）

But if you received an email or phone call from him, you can say

> どうやら彼は風邪をひいたらしい。（Apparently he caught a cold.）

So `どうやら` isn't necessary not always, but useful sometime.

