Its not a new thing to you hearing hygiene,starting from primary school,they were teaching us personal hygiene,so its not a new thing but let me spicy it a bit where you might have not touch before...Personal hygiene simply means personal cleaning thats keeping yourself neat always. Let me start from boys,imagine a boy wearing one boxer thats underwear over 4 to 5 days without washing,the odour that will be coming out from there,even some wear up to one week before they remember to wash it,some even say its not yet dirty coz they are looking the physical part of it and it look neat in they eyes thats why it not dirty yet for them..Do you know that you suppose not to wear any underwear more two times,it has an impact to your body system which can lead to infection...Some also dont brush their teeth,when they open their mouth people will run due to odour from your mouth...you suppose to brush your teeth at least once a day so it wont lead to mouth odour...Let me stop here for now,i am coming for girls part..