when someone tells me their reply rate has dropped, i don't guess.

i run the four pillars in order: infrastructure, then targeting, then offer, then copy.

that's the logical lens.

the reason most people don't diagnose properly is they change all four at the same time.

if you change four variables simultaneously, you have zero attribution on which one fixed or broke the thing.

you've got to isolate.

PILLAR 1: INFRASTRUCTURE CHECK

• are SPF, DKIM, DMARC all configured and green? yes / no
• is authentication passing on every sending domain? yes / no
• is warmup running in parallel with campaigns? yes / no
• is volume per inbox within safe range? yes / no
• is bounce rate under 1.5%? yes / no

if all five answers are yes, infrastructure is fine and you can move to pillar 2.

if any are no, fix that first and don't touch anything else.

PILLAR 2: TARGETING CHECK

• is the list actually your icp, or did you broaden it recently? _______
• are you emailing the right role at the right company size in the right industry? _______
• when was the list last verified or refreshed? ______ (if older than 30 days, re-verify)
• is the list too big for one hook to work across all of it? ______ (if yes, segment)

if targeting is drifting, you'll see flat opens and dropping reply rates.