I am starting to use sqlgrey and i find it very powerful
This a little and simple rule that give a little bonus to messages thet come from abitual senders
# Preferenza per chi non ha atteso sqlgrey
describe SQLGREY_WHITE AutoWhiteListed in SqlGrey
header SQLGREY_WHITE X-Greylist =~ /auto-whitelisted by SQLgrey/i
score SQLGREY_WHITE -0.15