Goines On: Save for 2030

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As Mrs. Goines took the 2019 Kew Botanical calendar off the kitchen wall, she asked Goines whether they should save it, “because we probably won’t live long enough to use it again.” Goines told her the calendar would apply again in 6 or 11 years, depending on when the next non-leap year started on the same day of the week as 2019: Tuesday.
    “If it’s only 6 years,” Goines said, “it’ll repeat in 2025, and we have to live until then – right? – because we’re going to Paris in 2026, for our 60th wedding anniversary.”
    He did a mental calculation to check when 2019 calendars would apply again. A year’s first day of the week shifts forward one from the preceding year, because there are 52 weeks in 365 days, plus one day, except after a leap year, in which case, because of the extra day in February, it shifts two days. And the total shift for a repeat has to be exactly 7 – or 14, if the combination of 365- & 366-day years causes 7 to be skipped over or it’s a leap year. Goines’ calculation revealed that a skip was going to happen in this case. Tuesday wouldn’t repeat in a non-leap year until the 11^th year, 2030.
    Living ten additional years from 2020 would be a bit more challenging for the Goineses than living just five more (or six-years-plus-four-months more for that 60th anniversary in Paris). Mrs. Goines said, “Maybe we’d better stick a note on the Kew Botanical calendar for our children: ‘Save for 2030’.”

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