Best Practices for Lead Enrichment and Outreach Strategies

I had a few questions regarding best practices for enriching leads/reaching out to leads. This is pretty confusing to me especially as I'm doing similar People searches across multiple tables....My goal is to: 1) not do the same enrichment (like find their work email) on the same person within X time period (e.g. within the same 6 months) 2) not send the same person to my smartlead campaign if they have been in a campaign (either recent or active) How should I handle this?