The probationary period also gives the new worker time to adjust to the responsibilities and expectations of the position. A company’s policies for probationary periods detail the evaluation criteria and the requirements for the new employee, supervisory staff and the human resource office.Businesses should seek legal assistance in developing probationary period policies.he period length may vary in the same company for different positions. Employers often exclude new employees from certain benefits -- including health care and leave -- promotions, transfers or raises until successful completion of the probationary period. Some companies include a provision for extending the period.