Why are internal sources of recruitment considered to be more economical?

Internal sources of recruitment are better than external sources of recruitment. Do you agree with this statement? Give any two reasons in support of your answer.
or
Why are internal sources of recruitment considered to be more economical?
Or
How can internal sources of recruitment be better than external sources? Give three reasons in support of your answer.
or
’Internal sources of recruitment are better than external sources of recruitment’. How? Explain by giving any four reasons.

Merits of internal sources :
(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 do not require much time, money and effort.