In my humble opinion, when there is a society that allows voting, be it at home, at school, in the city, or through governmental election, one must exercise her right to vote.
There is no home, no school, no city, and no government that is perfect. Knowing this, my electing to vote does not imply that I agree with all policies involved.
Also to vote doesn't mean my vote will be the elected vote.
My choosing to vote, in my opinion, just means that I believe that I have a voice and my voice is worthy of being heard and also that I agree to disagree.
These are the considerations I take into account before the election. What happens next belongs to the future, to be seen.
I vote at the society I live in where I am given the right.
Now in the upcoming Iranian presidential election, I would vote if I were reciting in Iran or if I had any plan or intention to live there in the near future.