DO provide assets or life insurance to pay estate taxes, to avoid tapping the IRA.
DO specify that beneficiaries can move the account to another bank or fund custodian.
DO allow your heirs to split the account after your death to spread out forced distributions.
DON'T name your estate as beneficiary. That will speed up distributions that deplete the IRA.
DON'T let the custodian dictate who inherits the account if a named beneficiary dies.
DON'T keep your account with a custodian that won't accept detailed estate instructions.