The Winningtemp standard when it comes to frequency is once a week to be able to measure temperature "in real-time", but it's up to your organisation to decide how often you get surveys from Winningtemp. You will also be able to get recommendations on how many questions per mailing you should have. The recommendations consider the number of active questions you have and the mailing frequency.
The time a survey is open depends on how often you send out surveys and can be calculated like this: the time between your surveys x 1.5. Meaning that, if you send out surveys weekly, they are open for 1.5 week.
As a system administrator, you can tweak the survey interval if you go to Admin view - Surveys > Standard survey > General settings.
2021-12-20 - Added read more section and added a new screenshot