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Salesforce also places limits on data storage, a total of 10GB for most production orgs. For very high traffic websites with a large number of visitor conversions additional data maintenance may be necessary.
Check the current Salesforce usage by searching for ‘Storage Usage’ in Setup.
Avoid identifying un-interesting website visitors. See Identified visitors section above.
Configure the Maximum Sessions and Store Event Data custom settings to avoid keeping un-wanted data.
Consider a scheduled job to delete visitor (send2crm__s2cVisitor__c) records that have not been modified for some time. The master-detail relationships will cause most related records to be deleted also, however this does not apply to lookup-related objects such as Leads and Contacts.