If alone, I'd almost always take the upgrade.
I've traveled with my parents before, and always added my mom as a companion for the upgrade, so that if we both clear, she and my dad can sit up front. A few times we've been sitting in good exit row seats and the GA comes on to say there is one seat in F, and would we want to split. Those times I've declined.
I've also asked to be put back in Y sometimes when flying with a friend I'd rather just sit and talk with.