Why you shouldn't send to purchased lists
A bought or scraped list wasn't built on consent, bounces and gets complaints far more often, and can be stopped at import.
A purchased, rented or scraped list is made up of addresses that never asked to hear from you. Far more of them are stale, mistyped, role addresses, or people who mark your mail as spam the moment it arrives. Each of those damages your sending reputation, and on shared infrastructure, indirectly everyone else’s too.
It’s checked at import, before you ever send
When you import a CSV, EmailFig checks the quality of the list. A list that looks acquired rather than collected doesn’t meet the bar, and importing it can suspend your account before a single campaign goes out. See This list doesn’t meet our import quality bar.
What passes the bar
Contacts you have genuine consent to email: people who signed up on your site or a form, gave you their address at a point of sale or event with clear notice, or came from a previous ESP where they’d already opted in with you specifically. Recency counts too: a list collected years ago and never mailed carries much the same risk.
What happens if you send to one anyway
Even a list that passes the import check can still cause trouble once you send: a spike in hard bounces, complaints, or recipients reporting they never signed up. A pattern of any of them can suspend sending on the account. See My account was suspended and Soft bounces vs hard bounces.
If you’re growing a list the right way, see Contacts, lists and tags: how they fit together and Import contacts from a CSV.