When you need something, you must have it. It is very important for you to have it. People need things.
"to necessitate" means "to cause to be needed", "to cause a need for".
People do not normally necessitate things. Situations or conditions necessitate actions.
not exactly...
you can see that what follows 'necessitate' is usually not a simple object or thing... but some kinds of actions...
http://sentence.yourdictionary.com/necessitate
example sentences:
That would necessitate raising the cost of the tours for guests. 25
10
On the other hand the modern view of the inspiration of the Scriptures does not necessitate the acceptance of the doctrine of the Scriptures on this subject as finally and absolutely authoritative. 5
6
The first type is in commonest use; since both necessitate the use of dense liquids, a summary of the media of most value, with their essential properties, will be given. 3
5
These crimes necessitate further acts of vengeance, and the curse is thus transmitted from generation to generation.