Basically, it means how long will the cookie consent still remain valid and after which they will expire and consent needs to be given again.
You can find this in Settings/Advanced Setting.
If you're on the Basic plan, this value is fixed at 7 days.
If you're on a Pro plan, you can change it to the number of day you want. If the value is set to 0, customers will be asked every time they access the website.