Arizona has a cost of living index of 110 relative to the US average of 100. This is above the national average. A FIRE portfolio in Arizona needs to stretch further. Many FIRE practitioners in AZ plan for a higher withdrawal need or consider relocating to lower-cost states.
The 4% safe withdrawal rule suggests a FIRE number of 25x annual expenses. At Arizona's median income of $81,486, that is $2,037,150. However, if you plan to spend more (or less) than median income in retirement, scale the number accordingly.
Arizona taxes income at 2.5% flat. In FIRE, your primary income comes from portfolio withdrawals, dividends, and capital gains. Long-term capital gains in AZ are taxed at the same rate as ordinary income, including IRA withdrawals. Factor this into your withdrawal rate planning.