HR is truely an experiencial stream. knowledge of best practices and theories, does not make one a good HR Professional. Human nature and reaction to situations are different for every individual. hence an HR Professional (here an HR ececutive who prepares salary sheets and documentation should not be mixed) develops over a period of time. for smaller companies with upto 50 employees, an experience of 3-5 years is required (this experience should be direct contact with employees, not back end processing). as you keep going up on the ladder of employee size, the experience keeps on increasing. however in organisations with over 200 - 250 employees (not labour) it is necessary to have an HR Professional who apart from experience of direct contact with employees should also have managerial experience, since he will have to control and guide subordinates who will have direct contact with employees.
Many companies have outsourced their HR department, which as per my personal view is calling for a disaster. you can outsource your backend office services but not the human contact. Outsourcing HR is like treating your employees as machines, who work for a particular time and get paid accordingly. HR deals with a varied mixture of attitudes and skills weighing which mix is acceptable and which is not. this judgement is highly subjective and can rarely be objectivised, desite claims of psychometrics proponents. psychometrics can only help an HR Professional in making a decision, it cannot be the sole decision factor.