most states require a will to be filed and or notarized
the more you do to make sure its NOT able to be contested the better
I have seen filed will's get contested when a PERSON shows up with a SO called different WILL, and sadly even seen them win at times, as some times it sadly comes down to who has the most money to fight for things
deaths can really bring out the greed in people and ruin families
so, the more you do to MAKE it so every I is dotted and T crossed the better, and in today's world, I personally have used a lawyer to video tape things, its a LOT harder for a scammer to make a video with different plans that you do if you make one.
My lawyer told me this was rather common anymore, and never been easy, he keeps TWO copy's as do I
its sad we have to do these things, but that's sadly how it goes when folks die more often than you think!