How often should the management evaluate the performance of an employee?

I suggest that a formal or semi-formal review of performance be done at least twice a year, since a once a year process isn't as helpful in helping you, the employee, modify or improve your performance, since often it's too late. Also, it's hard to remember what might have happened a year ago.

After the first 3 month of the employee starting date + one each 6 month + annually + before the employee promoted or transferred to another job + after finished the employee training

Performance Management System is a continuous process in any organization. It is important to sit with each employee at the beginning of every year to set his/her goal (targets / expectations by the org). An employee should be aware about his/her goals for the year to channel the work. KPI's will be the monitoring measures for the same.  According to the strength and size of the organization, the performance review can vary from quarterly to half yearly. This review is basically to convey the gaps and milestones to the employee to offer the support services to achieve the goals. It is necessary to have a half yearly employee evaluation process in an organization to achieve a consistent and predicable performance. 

every quarter at least and final appraisal every year 

This should be a constantly process and not restricted to a specific timeline or period. But care should be taken that it does not become micromanagement.

Sometimes people confuse a performance appraisal as an occasion for a compensation adjustment (raise) too. 

They should run parallel like two tracks of the railway.

Every six months, if not possible minimum yearly

Here is the response about performance evaluation only (not to be mixed up with appraisal or increments)

1. For a really fundamentally matured organization, half yearly review is fine.

2. For a startup or a new firm it should be earlier to ensure that nothing has deviated from the core strategy.

Thanks

If a company has established performance management system, they must be following KPI's to keep check on employees performance, which is done on quarterly basis. Usually your line manager to whom you are reporting is given the task to keep eye on employee's performance through KPI's which are provided to them by HR department, and HR department will prepare the KPI's by discussing the daily tasks and JD's of the employee to the line manager, because line manager is the person employee will be directly reporting to. Not only you can analyse employee's performance but you can also see if employee needs any training in a certain field. We can give employee either appreciation or warnings based on the result of KPI which we are doing on quarterly basis. This system is quite beneficial as it will keep the management informed about employee's performance, improvement or involvement in his work. And then there will be annual appraisal.

It is recommended to run the performance review once a year with a half-year interim review. Practice shows that the annual revaluation of each employee helps not just to set goals but to continuously follow  the corporate strategy and keep it alive.

Performance evaluation should be done twice in a year. Though the KRAs are set in the yearly appraisal meetings, it is always advisable to evaluate the agreed KRAs after 6 months to direct the employee in the right direction. But line managers should always keep an eye on KPIs of the employees to provide necessary suggestions whenever necessary.

It should be conducted in quarterly basis because of the keen competition. Updating and monitoring of  the skills will enhance the best outcome of individual  employees.