It’s fairly simple. If your tax bracket is the same or higher in retirement, the Roth is the way to go. If it will be lower, then Trad. This assumes that if you Max out your Trad, you also invest the tax savings into a brokerage account.
Beyond that, we can caveat things til kingdom come. I’d wager that a tax hike in the future is fairly likely, given that we are at pretty low rates historically. If you think your retirement income will be above lean fire amounts, you’re more susceptible to that type of change. A tax on Roth withdrawals could also be added, but I see that as much more unlikely since that’s basically the only defining feature of the account and would be a real dick move (Congress: Hold my beer).
Last, it should be noted that $1000 in a Roth is more than $1000 in a Trad, unless you can keep your retirement income in the 0% bracket (that’s a bit too lean to me). Many people aren’t saving or investing any money outside of their retirement account, so if they are just deciding on a set amount of money to put in one or the other, they’d be better off going Roth. Unfortunately, even more people are putting literally no money away anywhere, but that’s another discussion.
So, if you’re lean fire, you almost definitely want to be going Trad. If regular fire, whatever that means, you probably want to be going Trad, but figure out what your income will be in retirement (e.g. own a business or have rentals). If fatfire, it depends on how fat and what kind of income you’re getting, but your RMDs might be enough to put you over the tax edge of you had significant employer contributions, profit sharing, SEP, or Simple IRA.
I should have stopped after my first paragraph when I said “it’s fairly simple.” Le sigh