We send Mainteance Techs to training classes, but the problem is we don't retain our people after they are trained. Is there some sort of an agreement we can have employees sign agreeing to stay for a predetermined period of time? What else can

We send Mainteance Techs to training classes, but the problem is we don't retain our people after they are trained. Is there some sort of an agreement we can have employees sign agreeing to stay for a predetermined period of time? What else can we do to deal with this issue? Any suggestions would be appreciated.