While many students think that revision starts only after completion of the entire syllabus, this may not always be the case and there are exceptions for different subjects also. For instance, there are students who have a hard time retaining the things that they have learned while there are others who are more comfortable at it. In such cases, the students who find it difficult to remember the things that they have learned, can revise at regular intervals and not necessarily after completing the portion. Revision can be done after three or four topics have been finished, and at the end, a complete revision is also recommended.