Although most things are done together in marriage, there is no such thing as a "joint" estate plan. Spouses will have to have their own separate wills, powers of attorney, advanced medical directives and other documents. In some cases, couples might share a joint trust, but this is one of the few circumstances where there will be one estate planning document shared between two individuals. "Joint wills" exist and many people have heard of them, but this kind of document is rarely appropriate and most attorneys refuse to create them.
All that said, it is important for spouses to work together when planning their estates. Marital assets like bank accounts, real estate, investment accounts and other items of shared property tend to be intertwined, so it is vital that spouses agree on a plan for those assets should one or the other spouse pass away.
Furthermore, spouses have certain inheritance rights, and if one spouse tries to disinherit the other spouse in his or her estate plan, the disinherited spouse might be able to make a claim against the estate in probate court. Therefore, if spouses want to create an estate plan that does not fall in line with state inheritance laws, it is important that an attorney is involved and that both spouses are in agreement with the arrangements.
Spousal estate planning gets especially complicated if it is not the first marriage and one or both spouses have children from a previous marriage. In such circumstances, it is important for spouses to consider how they want their children to be treated versus their spouse, and -- again -- it is important that such plans are finalized in the legally appropriate fashion.
Source: nwitimes.com, "Spouses should work together when estate planning," Christopher Yugo, April. 12, 2015