Opzioni suggerite per la lungheza in spazi della tabulazione

:help tabstop recita:

1. Always keep 'tabstop' at 8, set 'softtabstop' and 'shiftwidth' to 4
  (or 3 or whatever you prefer) and use 'noexpandtab'.  Then Vim
   will use a mix of tabs and spaces, but typing Tab and BS will
   behave like a tab appears every 4 (or 3) characters.

Quindi usare:

set tabstop=8
set softtabstop
set shiftwidth=4