Should my powers of attorney be immediately effective?

Yes, your financial powers of attorney should be effective upon signing and if you become incapacitated. You want to have your named financial agent to be able to help you without a doctor having to declare you incapacitated. Once someone is declared incapacitated they lose the legal right to change their documents or handle their affairs. It may be that you are only sick and do not have the energy to argue with creditors. Even the elderly who have an onset of dementia have lucid times as well as times of diminished capacity. Therefore, name a trusted person as your financial agent, and a trusted alternate, and have them be able to help you immediately.