I've never found a reason not to vote, and plenty of reasons to vote. I vote in every election. You never know when that "right" is going to be stripped from you, and the Supreme Court race is reason enough to vote.
Just understanding the history of the franchise, and how it is subject to the whims of state and local officials is enough for me. Every vote, no matter for whom it is cast, is a blow against autocracy and exclusion.
My grandmother told me about the years when women couldn't vote in Iowa, yet they could in Wyoming. My mother told me about how racial minorities were excluded from voting, and my father-in-law related how he wasn't allowed to register to vote because he was an Indian. I go to vote out of respect for their struggles and their humiliation at being thought not capable of casting a vote.
I make sure I'm informed. If I can't find a candidate that matches my ideals, I vote for the least of the evils. I don't ever let the cynicism of the political elites discourage me from being a full fledged citizen. That's what the elites are counting on.