Are you referring to the API limit in your CRM? I'm assuming you are using Salesforce. We ran into this issue, but it was a combination of third party solutions and our own applications API calls that was pushing us over the limit. We ended up having to pay Salesforce to upgrade to a higher API limit.
Speaking of Salesforce limits, we recently overran our storage limit (a measly 1 GB) and Salesforce charges an exhorbinant amount for additional storage. One of the big culprits I found was actually Marketo. We were synching some of the "interesting moments" over to the Salesforce task object and that accounted for a huge percentage of our total storage. I ended up turning off all of the interesting moments synching because we have Sales Insight and that displays all of the info as well. I then purged all those records from Salesforce to get us back inline. Something to think about if you are worried about limits.