Ran a quick test today. Checked the battery level on my T-Mobile Dash Smartphone (Standard Edition). Then, I manually triggered Windows Mobile Messaging (email client) to check the Gmail IMAP4 mail server. After the the glacially slow mail sync completed, I checked the battery level again. It had dropped 4%. This explains why my battery levels became so low in the late afternoon when I had Messaging set to check Gmail once an hour. Ouch.