Microsoft introduced "Patch Tuesday" in October 2003 to reduce the cost of distributing patches after the Blaster worm.[10] This system accumulates security patches over a month, and dispatches them all on the second Tuesday of each month, an event for which system administrators may prepare. The following day, informally known as "Exploit Wednesday",[11] marks the time when exploits may appear in the wild which take advantage on unpatched machines of the newly announced vulnerabilities.
Tuesday was chosen as the optimal day of the week to distribute software patches. This is done to maximize the amount of time available before the upcoming weekend to correct any issues that might arise with those patches, while leaving Monday free to address other unexpected issues that might have arisen over the preceding weekend[citation needed].