Everyone needs something or someone at some point or the other in their lives. Necessities may vary from a person to person but the most important things like food, shelter, water and air is something that is unavoidable and necessary to survive on this planet. Though necessity is almost similar to necessary, both are completely different entities. Going by the dictionary definition, necessity is nothing but the condition or quality of being necessary. Read further for some great prerequisite /need quotations & sayings.