By being an employer people don't WANT to leave after 12 months
Guys there are plenty of good employers who over the years have done the right thing and have still been burnt by pilots. Noone is going to get 150K+ flying a turboprop. Reality is most people are going to join a jet airline if given the opportunity no matter how good your current employer is.
From my experience even if you hire older guys saying they'll hang around they usually bail too. That is the plight of those in the middle of the aviation food chain unfortunately.