If you are sitting for the SPM, Cambridge IGCSE or Cambridge International A Level examination, you may have heard of this rumour regarding the SPM, IGCSE or A Level examination from your teachers, friends or somewhere else:
"When answering structured questions, you cannot write your answer longer than the lines provided on the question paper. If you do that, the examiner will ignore and will not mark the part of your answer that is written outside the lines provided, so you will not be given marks for those parts of your answer. Therefore, the length of your answer is limited to the lines provided."
Here, I would like to clarify that the above statement is NOT TRUE. In reality, there is no limit on the length of your answer. No matter how long your answer is and no matter how much it exceeds the lines provided, the examiner will mark everything you have written and will give marks accordingly.
For SPM, a chief examiner had once confirmed that you can write your answer outside the lines provided if there is insufficient space. For Cambridge IGCSE and Cambridge International A Level, the Cambridge Learner Guide has clearly stated that you can continue writing your answer in any blank space if you have used all the lines provided.
For some subjects especially Biology, it may be desirable to write long answers. This is because the questions may not be straightforward, making it difficult to determine exactly what you need to write in your answer. By writing long answers, this increases your chance of having the correct points in your answer and getting the marks for the question, and you can avoid losing marks due to incomplete answers.
Nevertheless, you should not write your answer so long to the extent that you are wasting too much time on that question, as you may end up having insufficient time to finish answering the other questions. It is also important to ensure that you do not write any part of your answer in the 'For Examiner's Use' column, otherwise you may get penalised.
During my SPM and A Level examinations, a lot of my answers for Biology and some other subjects exceeded the lines provided on the question paper, yet I still scored grade A+ or A* for those subjects. This clearly proves that the rumour is not true.
However, please do not blame the person who told you about the rumour, since they must have heard of the rumour from somewhere as well. This rumour has spread very widely and I have seen many students discussing on internet forums about it. When it spreads very widely, many people will believe that it is true, even though it is not.