Should I be making my maximum allowable IRA contributions as early as possible in the year (for instance, Jan 1st 2023 for the 2023 contribution), or as late as possible in the year (for instance, April 15 2024 for the 2023 contribution).
I don't know if this answer is different for traditional or Roth IRAs. Depending on my income during the year, sometimes I contribute to traditional IRAs and sometimes I contribute to Roth.
Until I move the money to one of the IRAs, my money will be in taxable accounts invested in a portfolio of Vanguard index funds. My IRAs are also in Vanguard index funds, so the only difference is taxes.