It's up to you. I usually do 45 or 90 days and let the lead run through once every 90 days.
Inactivity is, in my mind, about Lead Behavior:
- Not Clicked AND
- Not Opened
- Not Filled Out Form
- Not Visited Page
the other items like Not Lead Score Changed or Not Program Status changed will depend on those behaviors, so I see no reason to use them. Marketo has a hard time processing these lists, so I try not to over think this one.
As for actual score amount, depends a bit on what your weightings are and how your database skews. Most firms do -5 or -10 every 90 days or so. Think through the implications of this of course.
Josh, do you run this set on ALL four behaviors? And then it's scheduled as a nightly batch that repeats every 30 days?
This might be an approach that was tested before, but how you guys done score delay for each element. for example:
TRIGGER: Visited A Key Page
FILTER: Change Behavior Score x points
Wait y days/months
Change Behavior Score -x points
I am trying to accomplish much of what you are trying to do. I have posted this idea that I think would be relevant to you: Non-linear Score Degradation (Percentage)
It would allow a percentage-decrease in scoring to better reflect how the conversion-likelihood of a lead drops off with the passage of time. Please upvote and comment on it if you feel inclined