A developer on the Team plan asked

We are about to go from 40,000 to roughly 600,000 emails a month in one release. Do we need to warm anything up, or does the shared pool handle a jump like that?

Arvo support replied

At 600k you want a dedicated IP, and the warm-up is the part that needs planning rather than the send itself. Two weeks, roughly doubling daily volume, starting before the release rather than on the day. The shared pool will technically accept the jump — and your open rates will tell you it was a bad idea about four days later. If the release date is fixed and it is inside two weeks, stay on shared and move after. A rushed warm-up is worse than no warm-up.

Arvo Support · replied 14:06 GMT