If my memory serves me right, among others, the times we see Michael smoking – not very many [just seven?] four in Godfather and three in Godfather 2

1. Waiting to find out where the meeting with Sollozzo and McCluskey was to take place
2. Fish tank scene
3. Meeting with Moe Greene
4. Kay asking Michael whether Michael had Carlo killed
5. Meeting with Senator Geary
6. Hotel Washington scene
7. Vito's birthday flashback scene