If you know that you're making a change on a particular day, then you should be able to schedule a microsurvey for that particular day, or for the week before or after that day, in advance, and to have it stop automatically at your end point.
- Allow maintainers schedule an individual survey to start on a specified day and time.
- Offer to stop the survey (perhaps a default of 30 days?).
- Offer "indefinite" as a survey length (should not be used for most surveys, but will be needed for some).
- Make it possible to change the dates after the survey has started (because deployments don't always happen when scheduled).