Currently, I send emails to a small list (2000) as a solpreneur consultant. I'm planning to grow my business and my list this coming year, but wouldn't expect to have more than 10,000 subscribers and send between 40,000 at the low end, and 150,000 total emails per month at peak during a launch (for example).

My Google Postmaster Tools report shows my domain reputation as High, and my Spam rate as under 0.5% I currently have DMARC set up on my sending domain.

Do I need this tool, and would it be helpful to someone in my situation, given the growth I'm anticipating?