B2B contact data degrades at roughly two to three percent a month, faster in technology and startups where tenure is short. Over a year, a third of a static file can be stale.

Decay shows up as bounced emails, dead numbers and, worst of all, people who answer but left the company two years ago. The last category costs the most because it burns a live conversation.

The fix is not a bigger file, it is fresher sourcing. A list built the week you call it beats a list of ten times the size built last year.