[kiallmacinnes]

Once you hit this limit, you are not prevented from renewing existing certs.

You do have to be a little careful, for example adding a new SAN to a cert might fail due to 20-per-domain-per-week limits, attempting to renew that cert without removing the extra SAN will fail.

[justinsb]

Thanks for the note on the renewals (and the caveat!) - that does make it less concerning as it would only impact new services.