Recently I was asked if it would be possible to set the Presonalization checkbox on the delivery tab in EXM by default. Since all of the emails were being personalized, the client did not want to have to remember to manually check the box every time they went to deliver and email campaign.
In Sitecore 9.0.2, this can be done by navigating to:
/sitecore/templates/System/Email/Messages/Mail Message/__Standard Values
Check This email uses Personalisation and that is it. The checkbox will now be checked by default when you create an email campaign. It should be noted that the location is a little different in newer versions. Hope someone finds this tidbit helpful.
15+ year programming professional with 10+ years devoted to Sitecore development. I've been using the platform since Sitecore 6.0 and currently serve as a Technical Architect at Verndale.