Creditors have up to four months to submit claims and the personal representative may, but need not, delay distribution until the end of the creditors' claim period. A trustee may also have to delay distribution in order to pay taxes or liquidate assets in order to divide property. An improperly prepared or funded trust may require money and time to correct before distribution can be carried out. Probate forces the liquidation of your assets. A trust is no guarantee against such liquidation for the same purposes.
Probate litigation is expensive.
Expenses will depend on the nature of the litigation. Wills can be contested. But there is no reason to expect that a properly drawn will is going to be contested. A trust will avoid Federal estate taxes. Arizona does not have an inheritance tax.