Some suggestion is that if we plan to have lower tax bracket when we retire, we can contribute into 401(k) pre-tax instead of after-tax.
However, if some people may contribute $60,000 into either pre-tax or after-tax, then when they retire, if it has $1.5 million, then they may end up with $1.2 million after paying tax, versus if people contributed for after-tax, they have $1.5 million, and it is always $1.5 million. They don't have to worry about tax for it at all.
So is it true that we may consider after-tax even if we think our tax bracket is low after retirement?
But one exception may be: I can't recall if it is after-tax, is it true that some company may not match your contribution, say, at 100%. If it is 100%, then you may considered it "paying for your tax" already, because if you have $100 and the company contribute $100, then you have $200. Even after paying tax, you may still have $120, so it is better than paying tax for you.