What are the internal sources of recruitment?

What are the internal sources of recruitment? State any four advantages and four limitations of internal sources of recruitment.
or
Filling vacancies from within the organisation has some advantages as well as limitations. Explain any three such advantages and any three limitations.

Internal sources refer to recruitment from within the organisation. Sources of internal recruitment are—
(i) Promotions
[ii) Transfers
Limitations of internal sources of recruitment :
(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 transferred 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.