as long as / as far as

【接続詞】as long as ... 　...する間は《時間》=while
You can stay here as long as you want.
As long as he is here, I'm too nervous to eat anything.
(While he is here, I'm too nervous to eat anything.)

【接続詞】as long as ... 　...さえすれば《条件》=only if, provided
You can have a dog as long as you promise to take care of it.
I am happy as long as my family is happy.
(I am happy only if my family is happy.)

【接続詞】as far as... 　...する限り《程度･範囲》
As far as I'm concerned, you should not keep in touch with her anymore.
 concern v)...に関する、心配させる、不安にさせる

 As far as I'm concerned, 〔慣用句〕私としては、、（私に関する限りでは）
 As far as I know,　私の知っている限りでは
 As far as I (can) see,　私の見る限りでは
 As far as I (can) tell,  私の言える限りでは
 As fat as I (can) remember,  私の覚えている限りでは
 As far as the eye can see,　見渡せる限りでは
 As far as the eye can reach,　目が行き届く限りでは

As far as I remember, his name is Steven.
As far as I know, the marathon course is blocked with(by) fallen trees.
Well, as far as I remember, your name is...