I'm the odd man out - I delete, delete, delete
I triple check my layout before saving for spelling mistakes and if it still gets past me then I chalk it up to being human - I'm definitely not perfect and if an occasional layout shows that then it doesn't bother me. In the 6 years I've been digi scrapping there hasn't been a time when I wished I had saved a PSD file, so I don't waste the space keeping them.