Should follow-ups be in the same thread or new ones?

Threading decisions affect both deliverability and recipient perception.

Same thread (reply-style) advantages:

Maintains conversation context

Appears more personal and human

Recipients can see the history

Some filters treat replies differently than new messages

Higher likelihood of being noticed in a cluttered inbox

Same thread disadvantages:

Long threads can look aggressive

Previous messages may have been spam-filtered (making replies invisible)

Some recipients find persistent threads annoying

New thread advantages:

Fresh start each time

Different subject lines can test messaging

May reach recipients who filtered the original

New thread disadvantages:

Loses conversational context

Can appear like multiple spam attempts

Each message stands alone without relationship building

Common practice: Most cold email tools use same-thread follow-ups as the default. This mimics genuine human follow-up behavior. New threads are typically reserved for major message pivots or when starting entirely new campaigns to the same list.