That time you and a source or an editor exchanged 15 emails before finding a time that works for both of you? So 2015.
Last year, after several lengthy email exchanges, I began experimenting with a new system. Rather than comparing schedules over email, I now send contacts a link via the free version of Youcanbook.me, which is synced with my Google calendar. Contacts can look at my schedule and book a time that works for them. This simple tweak to my process has freed up time I would normally spend emailing, which means more time to write.