Some of the disadvantages of using an agile model are as follows:
a) Not easy to predict: When you encounter a large project, it is not easy to get an idea of how much effort will it need
b) If the guidelines given by the customers is not properly grasped, then the final outcome of the project is not customer satisfying
c) Sometimes focusing on design and documentation is not proper
d) High-level decisions are under the hand of Veterans, if not combined with non-experienced one, freshers have little scope to grasp proper knowledge.