Per task (follow up) you can give a certain amount of time in days to follow up.
Here you see the default setting and can adjust these values anywhere.
For a customer it is usually important that the response days are higher dan a lead.
vb: if i do a follow up with a prospect and choose the task ‘Callback appointment’ i can set it in my calendar between a range of 90 day’s. I cannot set a dat over the 90 day’s.