Enrich on entry, before routing and scoring, and only the fields your rules actually consume — company size, industry, domain-to-account match, and whatever your segment boundary is defined on. Enriching fields no rule reads is spend with no decision attached.
Enrichment as a category reaches about 70% of high-growth GTM stacks, so the question is rarely whether but what and when. Build an explicit enrich-status field and a fallback path: records the provider can't resolve need a queue with an owner rather than silently failing the routing rules.
Every claim above comes from work LeanScale published. These are the sources.