"Joint Tenancy" is a form of holding title to property (real property or personal property). Other forms of holding title to property include: community property, tenants-in-common and a single person as their sole and separate property. Holding title as a joint tenant with someone else (usually your spouse) does not avoid probate-it only postpones probate until the death of the surviving spouse. Moreover, by holding title as a joint tenant, you adversely affect the income tax "basis" of your assets because the surviving spouse only receives a 50% "step-up" in basis following the death of the first spouse. This could result in the surviving spouse having to pay unnecessary income taxes if any assets were sold following the death of the first spouse. If you are married, it is much better from an income tax perspective to hold title to your assets as "community property". That way, following the death of the first spouse, the surviving spouse receives a 100% "step-up" in basis and, if an asset were sold, would not have to pay any income taxes. Finally, most people are now aware of the fact that it is not a good idea to add your children on title to your assets as joint tenants; doing so means that:

1. you need your children's signatures to sell or mortgage your assets; the assets are exposed to your children's creditors (including possible claims by a child's ex-spouse in the event of a divorce); you create potential "gift tax" problems; and
2. you create potential income tax problems for your children with respect to the "cost basis" that passes from you to your children when you make a gift of an appreciated asset.