And to be fair, my advice will change if VTIAX has the same dividend as VTSAX, but it hasn't for many years now.
I also wanted to add it may be worth "tax loss harvesting" in a taxable account, which is easiest if you have both U.S. and international there. Whichever one drops within a year or so of buying it, you can sell to realize the loss (the IRS shares your loss, essentially, provided you follow their rules).
If you already have an allocation with unrealized gains (meaning it will incur taxes to sell), I'd just keep it.