necessary means if do you think you should be doing that or do you feel that your doing the right thing "do you feel that's necessary"
If you have made a Will..on the otherhand you are in effect making your wishes known very clearly as to who gets what from your estate...i.e.."I wish to leave my house to my wife Jane-and I wish to...
necessary (essential or required)
The Necessaries is the group known for 'You Can Borrow My Car'