If there is a really small estate, is probate still necessary?

Possibly. In some states, there are processes often referred to as “simplified procedures” that are used for estates whose value is below certain financial thresholds. The limits can be as small as a few thousand dollars or as much as a hundred thousand dollars. It depends on the court of jurisdiction. This is certainly a matter to consult with an attorney about, but if there is real estate involved or there are debts against the estate, regardless of the size of the estate, the full probate process may be required or advisable.