Quote Originally Posted by oldboy View Post
For example, If I had more time I should learn Japanese. Here should has the same meaning as would. That is, it would be possible to say [I]If I had more time I would learn Japanese.
I would stick with "would" in all cases. You can say "should" but in the US you never hear people talk like that, it sounds kind of stuffy or pedantic. I'm not an expert on usage in Britain but from what I understand the use of "should" in such cases is mostly a thing of the past and you're best advised to use "would."