My main use case for AoC is practice with new languages. So I tend to prefer to do the same one from several years ago over and over, because then I can focus on grokking the language and not the problem, and I can compare my solutions across languages to get a better feel for how they affect how I solve problems.

The leaderboard is occasionally interesting to me for the first week of December, but, realistically, I can't see getting invested in it without also moving far, far to the west of where I live now.