Extraordinary days will be ordinary
nThen, the extraordinary days when Derek has a big project to work on or receives 80 e‑mails will not be a burden.  He may have to delay responses for a day or two, but then he will catch up and maintain the two-hour set point. 
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nIn those cases, he will e‑mail people within two hours as usual saying he’s not able to respond adequately, so it may take him a day or two to get back to the sender. 
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