One other thing is it's fairly common to have at least two general buckets of investments: "Old (wo)man money" and "young (wo)man money." Young man money is generally taxable investments and accounts (plain old stocks, bonds, mutual funds held in brokerage accounts, real estate), while old man money is tax-advantaged accounts like 401k's and IRAs.
Typically, you could draw down on principal of the taxable accounts, and even deplete them completely, until you're 59.5 and eligible to start withdrawing from your 401k/IRA without penalty*. On balance, though, the old man accounts should go up as much as, or more than, you're taking out of the young man accounts. So, if you depleted your taxable accounts by $400k to cover living expenses until you reached 59.5, then your 401k/IRA will hopefully have gone up by at least $400k (in real, inflation-adjusted dollars) in that time. At that point, you switch to withdrawing from those accounts to cover your living expenses.
Therefore, you don't have to be too concerned about eating through the principal of certain accounts as long as your total net worth is mostly remaining the same, or hopefully even going up**.
* You can also access 401k's and IRAs before age 59.5 and without penalty using the various methods like 72t withdrawals and Roth conversion pipeline.
** There could also be fluctuations in your net worth, of course, due to market swings. It will not likely be a perfect straight line. Over the long haul, though, by following a Safe Withdrawal Rate like 4%, one should hope their net worth remains the same or increases.