Mailivery recommends keeping all connected email accounts active rather than disconnecting them. Instead, keep them warm permanently.
Here is why:
Your average response rate to sales and marketing emails is 1%. Just having to "warm up" an email account is a misperception from email marketing.
Your true goal is not to warm up an email but to bring the email to a natural state by means of a natural overall average response rate.
In other words, Mailivery is the service that brings your total response rate (your real emails + Mailivery emails) to a natural state. As soon as you deactivate Mailivery, your response rate goes to abnormal again, and you land in spam more often, again.