Rotation, caps, and warmup

Mailboxes has its own area in the nav because rotation, caps, and warmup are things you monitor, not settings you fill in once.

Rotation

With more than one mailbox connected, each send goes to the one used longest ago. A mailbox that has never sent is first in line. Disabling a mailbox takes it out of rotation and changes nothing else.

Caps

Each mailbox has its own daily cap, and the workspace has one too. A send that would cross either cap waits for the next day instead of being dropped.

Warmup

A new mailbox with no sending history looks suspicious to receiving servers. Start a warmup and its usable cap begins low and climbs toward the full daily cap over the following days. A mailbox with no warmup ramp can use its full cap immediately.