As usual and As before

[zongzong]

I always hear about say: As usual，........ and I know "as before" also is a correct expression.what's more,the meaning are the similiar to each other.

I want to know how to distinguish between them?When we should say "As before" and whem we should say "As usual"?

Thanks a lot

[Tdol]

They're not the same to me- as usual = in the normal manner as before = in the same way as previously

[zongzong]

Ok,I see.Thanks