As a person who has cleared all the competitive examinations (in which he appeared) for Government jobs without attending any coaching institute, I would like to state the following few facts:-
(i) A student/candidate must understand that the pattern of questions of every compettive examination is different from other.
(ii) Every candidate must explore the question papers of previous years and sample papers (of a particular examination) to have a feel about the questions.
(iii) The stress area of a particular competitive examination is diiferent from the stress area of another competitive examination. As for example, in banking service recruitment examination, in General Knowledge, stress is given on current affairs and economic data, whereas in Staff Selection Commission examinations, in General Knowledge, stress is given on classical GK.
(iv) A candidate goes for coaching when he/she fails to understand the pattern of a particular competitive examination.
(v) So a candidate must expect the followings from a coaching institute: (a) Clear guidance about the pattern of question papers of a particular competitive examination; (b) identifying the stress areas; (c) adequate practice of sample papers of a particular examination with time-management; and (d) clearing the doubts and strengthening the weak areas of individual candidates.
Caution: Explosive. Handle with care.