Staffing refers to putting right people on the right job.It begins with workforce planning and includes other functions like recruitment, selection, training, development, promotion, compensation and performance appraisal of workforce.
Staffing is an important function of management.Following points highlight the same:
(i) Staffing ensures the availability of the most suitable and capable persons for various jobs.
(ii) By placing the right person at the right job, it ensures better performance.
(iii) Staffing ensures the continuous survival and growth of the enterprise, through the succession planning for managers.
(iv) It helps in avoiding over manning, under utilisation of manpower and high labour cost.It also helps in preventing the disruption of work by indicating in advance about the likely shortage of employees.
(v) It improves job satisfaction by providing fair remuneration and regular assessment.

Yes, staffing function is considered key to other functions of management because all other managerial functions depend on staffing.In fact, the effectiveness of other managerial functions depends on the effectiveness of the staffing function.
If an organisation employs right person, this will increase the work efficiency of an organisation.Thus, efficient staffing helps to improve the quality of planning, organisation, directing, and controlling.

There is involvement of the managers in staffing for which staffing can be accounted for the following reasons:
(i) Desire to build up for future, a competent team of successors.
(ii) Managers desire to ensure the proper and successful functioning of the department with the help of competent staff.

It is because of
(i) Rapid advancement of technology.
(ii) Increasing size of organisations.
(iii) Complicated behaviour of human beings.

i) Development of Backward areas.
ii) Helpful in availing trained employees.
iii) Increase in productivity and boosting the morale of employees.
iv) Increase in employment opportunities.

i) Biasness
ii)Biased Behaviour.
iii) Misuse of rights.
iv) Insecurity and groupism in employees

Staffing helps in obtaining right people and putting them on the right place/jobs.

Staffing helps in obtaining right people and putting them on the right place/jobs.

Staffing helps in obtaining right people and putting them on the right place/jobs.

Internal sources refer to recruitment from within the organisation.Sources of internal recruitment are:
(i) Promotions
(ii) Transfers
Internal sources of recruitment suffer from the following advantages:
(i) Employee motivation Promotion to a higher level motivates the employee for better performance and leads to satisfaction of employees.
(ii) Simple process  The process of selection and placement becomes simpler, as the background of the candidate is already known.
(iii) Facilitate training  Transfer from one job to another facilitates training of employees.
(iv) No induction training  Employees selected from within the organisation do not need induction training.
(v) Filling deficiencies It helps to fulfill the deficiency of one department with the surplus of another.
(vi) Inexpensive  Recruitment from internal sources does not require much time, money and effort.
Limitations of Internal Sources
Internal sources of recruitment suffer from the following limitations.
(i) No fresh talent    Recruitment from internal sources does not bring fresh talent into the organisation.
(ii) Lethargic employees   When employees are sure of time-bound promotions, they become lethargic.
(iii) No competitive spirit   Competitive spirit among the employees may get hampered.
(iv) Reduce productivity   When employees are transformed frequently to different jobs, it results in reduced productivity.
(v) Not available to new enterprises   A new enterprise cannot avail the benefit of this source.

Internal sources refer to recruitment from within the organisation.Sources of internal recruitment are:
(i) Promotions
(ii) Transfers
Internal sources of recruitment suffer from the following advantages:
(i) Employee motivation Promotion to a higher level motivates the employee for better performance and leads to satisfaction of employees.
(ii) Simple process  The process of selection and placement becomes simpler, as the background of the candidate is already known.
(iii) Facilitate training  Transfer from one job to another facilitates training of employees.
(iv) No induction training  Employees selected from within the organisation do not need induction training.
(v) Filling deficiencies It helps to fulfill the deficiency of one department with the surplus of another.
(vi) Inexpensive  Recruitment from internal sources does not require much time, money and effort.
Limitations of Internal Sources
Internal sources of recruitment suffer from the following limitations.
(i) No fresh talent    Recruitment from internal sources does not bring fresh talent into the organisation.
(ii) Lethargic employees   When employees are sure of time-bound promotions, they become lethargic.
(iii) No competitive spirit   Competitive spirit among the employees may get hampered.
(iv) Reduce productivity   When employees are transformed frequently to different jobs, it results in reduced productivity.
(v) Not available to new enterprises   A new enterprise cannot avail the benefit of this source.