I have a database of around 1.2mil emails that I have purchased from various sources and send around 400k each month from an ESP I have been with for the last few years. My lists appear to be clean. I currently get approx 8% open rate. I manually remove bounces so my current bounce rate typically is around 1%. My lists are focused on my niche and we are 100% compliant with CAN-SPAM. I would like to get a better open rate if possible. I read through the terms and conditions of all these different ESP's and every single one requires 'opt-in.' Is this just them covering themselves or will you get dropped for sending to emails that have not opted in? Is 8% good? Will switching to a better quality ESP yield greater results?