The I.R.S. is giving widows and widowers more time to deal with complicated estates after one spouse dies. Typically, when one spouse dies, the other one gets all or part of the estate tax-free. The surviving spouse can also carry over the deceased’s unused estate tax exclusion if they file an estate tax return and choose what the IRS terms “portability.” Previously, a surviving spouse had only 15 months to file the return. Under new rules, however, the window for filing was extended to two years in 2017 and then last week it was raised again to five years. Talk to your tax accountant if you have any questions about the new rule.