Oh for a change of batteries... East Derwent Highway, Geilston Bay. August 2011.
It seems to have been grey and raining in Hobart for the past fortnight. I expect that this is my memory playing tricks on me and it has actually been just six days; but a more complex equation seems more realistic:
6 days x [1 three year old + 1 four year old] = 27.73 days (equivalent).
I'll be frank and suggest that the multiplier probably needs tweaking, given the particular force of the psychological correlate of Henry's immense physical strength (from an amplitude perspective) [i.e. he is very loud]; and the increasing frequency of Ezra's manifestation of a loss of control and frustration [i.e. temper tantrums].