I was working at a pretty poorly run company and money was tight. I saw that we were spending WAY WAY too much on our ESP for the amount of subscribers we had, and how many emails we sent out (maybe 1-3 per client a month). I went full on research mode for about a month, and got cost-breakdowns for every ESP I could find, and laid it all out for my supervisors + CEO. Gave them a presentation about why I wanted to use the ESP that I did, and how much money we'd be saving over time for a better ESP with more functionality. That won them over, and we switched over 100+ accounts last summer.