The concept of a joint will is something strange to me. Especially in modern times where couples are fairly independent, compared to 50 years ago. The concept of a joint will may have made sense in the times when people got married with marital power regime (before 1984), where the woman was literally governed by her husband and she couldn't make any decisions on her own.

But times have changed and we are all more independent. People tend to think that having a joint will saves them money (as it's one will, instead of two), but it just makes no sense. The reason for this is the following:

The only time a joint will is an acceptable idea (not good, acceptable) is when a couple wishes to leave all their assets to the other upon their passing and they are at ease with how the spouse will manage their money or don’t care what happens with it after that point OR if they die simultaneously.

When the first testator of a joint will dies, the other testator chooses whether they accept or reject this joint will as their own.

If they accept it, they can never draft a new updated will again. That may be fine if you’re 90, but not when you’re 50. People move on with their lives, remarry and children can pass away before their parents. Once they’ve accepted this joint will, there’s no room for change later.

If they reject the joint will, they are free to draft a new will to express their wishes. That’s great for the surviving spouse, but in effect the first dying’s wishes are not 100% adhered to as (s)he envisioned.

So best way to ensure your wishes are adhered to 100% is by drafting your own will.