I'm new to Marketo and trying to reduce the size of our database to keep it under 10,000. Right now we have almost 14,000 leads in Marketo, but we are not actively marketing to a large portion of them. Would it make sense to remove everyone who is not part of a Sales Generated List or List Purchase Program and who has not visited our website in the last 2 years? Trying to figure out how this would impact our data and MSI once it is set up. Thank you!
"Visited web site" is probably not the best non-activity you would want to look at. You can only tell if somebody visits your website if you have cookied him, which usually implies that they also have submitted a form. So you might delete persons who are actually good data, but you just don't track their web site activity.
Also, you might consider whether or not these persons are synced with your CRM.
From my perspective the best indicators for inactivity would be:
Has not been sent any email
Don't have any contractual situation with you, like a purchase or a trial
Take a look at these numbers and see if that already reduces your database size significantly.
Curious why you want to keep under 10k, what industry are you in? That seems pretty small.
Also just a caveat that "visited web page" only goes back 90 days so it's not a great filter for history, plus as mentioned already you would miss anyone not cookied https://nation.marketo.com/t5/Knowledgebase/Marketo-Activities-Data-Retention-Policy-Under-the-Hood/...
I would maybe look at people who are unsubscribed, not member of any marketing programs, no sales activity or sales disqualified.