How did you fairly divide a shared vacation home?

If it were my family, I would divide the number of weeks by the number of owners. I wouldn’t try to “lock in” specific weeks for every year, because someone will ultimately feel cheated. Maybe rotate 1st pick annually, and 1st pick becomes last pick the next year. Pick a week at a time and rotate through family members until the calendar is full. Hopefully you’re accommodating and caring enough to listen to other owners if something pressing comes up out of the normal rotation.
And family is important. It would be nice if you could overlap and spend time as a bigger group some. Like an annual get-together week.

Freestyle Streetfighting Tournament.
Winner takes all, the rest sleep outside.

Can each family choose more than one week? Dividing the summer into weeks will work well. Got to figure out what the transition day will be, like “depart by 1 pm Sunday, arrive after 1 Sunday”.

Put a number on a slip of paper for each family, and then each family draws a number out of a hat (or a paper bag) and gets the order in which it chooses. For instance, five families, put slips numbered from one to five. First to draw a number may pick 4, the second might pick 2, the third 1, etc. That’s the order they choose in.

If there is enough room to choose a second week, reverse the original order, so the picks go 1,2,3,4,5,5,4,3,2,1.

And who ever drew first this year will automatically draw last next year, but the other families will draw the order out of a hat again next year.

I could see something like a shared vacation home turning into bickering or resentments, over who got what or who got exceptions or someone not being able to leave on time or whatever. It almost seems like more trouble than it’s worth.

We had 5 families that each got 2 weeks at the cabin. Each year a different family would get to pick first the 2 weeks they wanted that summer and it would rotate in order through the other 4 families. The order would reverse for any of the other weeks or weekends left. Never had any issues that I can recall other than my rich Prima donna Uncle loudly moaning when he would be stuck with the 2 weeks in June.

I don’t have a family vacation home, but rotating the first pick sounds fair to me. I could see that being a problem in my husband’s family, because their ability to plan ahead is for shit. So, I would put some sort of date it needs to be decided by or you give up your place for that year. Not give up your ability to stay at the house, but your ability to choose the date. Another problem is his family can suck at communicating. I would hope if someone was not going to use the house or only stay a long weekend they would let everyone else know so they can stay longer if they wanted to, but his family would not necessarily think about others in that way.