Joint ownership is the simplest and least expensive form of incapacity protection. Your elderly uncle who is becoming forgetful, for example, might put his bank and brokerage accounts in joint name with your sister Gwen, who lives nearby. Then, if your uncle no longer can handle his own finances, Gwen can write checks, reinvest bond interest, and so on.

The catch? Such joint accounts typically are titled “with right of survivorship.” When your uncle dies, Gwen will become the owner of those bank and brokerage accounts. No matter what your uncle put in his will, you and other relatives will be shut out.

Therefore, you shouldn’t encourage elderly loved ones to rely too heavily on joint ownership. They might keep a small amount in a joint checking account for paying bills. Beyond that, they can transfer assets into a trust and give someone a power of attorney for assets not held in trust–these tactics will provide incapacity protection without disrupting an estate plan.

Joint ownership comes in three varieties:

1. Joint tenancy with the right of survivorship. As the name suggests, if one co-owner dies, the survivor becomes the sole owner.

2. Tenancy by the entirety. Offered in some states, this type of ownership is generally available for real estate owned by a married couple. Again, the survivor automatically inherits. If property is titled this way, it’s out of the reach of creditors of either spouse, as long as both spouses are alive.

3. Tenancy in common. Here, each co-owner holds a share of the property outright. That portion can be transferred to anyone by sale, gift, or bequest.

Joint ownership with right of survivorship is the most common form. Among the advantages are probate avoidance and incapacity planning. If one co-owner becomes incompetent or dies, the other one takes over right away.

On the downside, one co-owner will always inherit from the other. Therefore, joint ownership won’t be a good idea for assets you wish to leave to someone besides your co-owner.