I have a blob of money in an intermediate-term tax-free acount but with its NAV so high I would hesitate to add anything to it (I take its monthly dividends in cash because I use them towards my monthly expenses) because its NAV could fall by more than any tax-free interest could offset that drop in value. And in the 18 years I have been in this fund I have found that when the NAV falls, it falls very quickly.
Retired in late 2008 at age 45. Cashed in company stock, bought a lot of shares in a big bond fund and am living nicely off its dividends. IRA, SS, and a pension await me at age 60 and later. No kids, no debts.