I've seen firsthand what headaches not having a will can cause.
Even with one there can be headaches. One of my residents died and she had everything in a trust. Well, once you die, the trust dies with you and the will takes over, which she had with 11 beneficiaries.
I listed her home and had an offer really quick (as in she accepted the offer but died before signing the title). Her idiot lawyer who set up the trust told her to take her 2 daughters off the title. Because the title wasn't signed I had to get signatures from ELEVEN people scattered across the US, waiving their right to the home just so I could get it transferred to the new owner. If her daughters were on the title as an "or" (Jane Doe or Mary Smith) there would be no issue as one of them could have signed it.
I still have nightmares.