3-6 month trial/probation is fairly common. While it does help both sides familiarise with each other, it can't prevent a conflict in the future.
I've dealt with long time (15 years) employees suddenly or gradually going completely nuts - refusing to perform any meaningful task, accusing others of abuse and just playing dirty for months, sometimes years.
It's no fun, I tell you what! 6 months trials are useful but to a point