Great question about the third conditional! Sure, if you only use one 'had' people will understand you, but no, unfortunately it is not correct. We don't use the third conditional very often, but we do use it in specific situations, and it is complicated. The third conditional is used when we want to talk about something that *didn't* happen in the past - and what the possible consequences would have been. Just a refresher - here is the construction for the third conditional: If + past perfect, would + present perfect (past perfect = had + the past participle, present perfect = have + the past participle) So: If I HAD HAD a billion dollars when I was 16, I WOULDN'T HAVE BEEN homeless. This is pretty much one of the most complicated grammar structures in English! Here's a helpful tip that will prevent you from having to say "If I HAD HAD" - use the contraction! As a native speaker, I would always say "If I'D HAD 1 billion dollars..." because you're right - it's totally awkward to say "had had!" I hope this is helpful! - Sarah https://www.italki.com/teacher/3458152