With regard to personal things, discuss with siblings. One of mine gave away my mother's sewing machine to a friend. I learned to sew on that machine and found it much easier to use than my own and the model is no longer made. Seems like NBD, but when one or another sibling does this repeatedly, it causes hard feelings.
Also, if there are certain things that more than one person wants, maybe parents can help sort that out before their death. My mom informed us all who got which pieces of furniture. So when she died, the designated person just took the piece with no hard feelings by anyone else.