This subject has seen minimal discussion on this forum, but it's very important. There is much discussion here of accumulating wealth and storing it, but little discussion of preparing for the worst case scenario of one's demise (other than the occasional joke about one's widow dumping depositing their silver coins at the bank or dumping their bulk coppers into the Coinstar).
You absolutely need a will, and to update it regularly. I offer three anecdotes from my own life over past few years:
1) An older relative with a wife, kids, and business was scheduled for life threatening surgery and did not survive the operation. They had no will, and their assets have been tied up in probate for years. Their widow was left with a mountain of paperwork to untangle.
2) A friend's only surviving parent was diagnosed with stage 4 cancer and died a year later without updating their will! The original named executor of the will is estranged from the family, and as a result the two siblings are fighting over the house and money, both legally and physically. The whole mess could have been avoided had an updated will existed, and the deceased had plenty of time to do some estate planning.
3) A distant relative passed and had several firearms in their possession. Their immediate relatives cleaned out the house and didn't know what to do with the collection of firearms, so they turned them over to the police. Among these was a Colt King Cobra, which sells for about $4,000 right now.
So the next time you're prepping, update your will. Don't leave a mess for your friends and family to deal with, and don't let your lifetime of hard work and investing be consumed by probate.