An Odd Halachic (Jewish-Law-Related) Question

[gnomi]

Now, I know one is not supposed to go psak shopping (that is, one should not ask the same question of multiple rabbis until one gets the answer one likes). However, is there a statute of limitations (as it were) on asking a question and not receiving an answer at all before you can pose it to a second rabbi? In other words, if I sent a question with some time sensitivity to Rabbi A, how long do I have to wait for an answer before I can feel comfortable sending the question to Rabbi B?

(not a current concern; I'm just wondering)