Email sender reputation is like your credit score; it takes a time to build, and you control it. Dedicated IP address allows you to be in charge of your email delivery.
Your sender reputation is critical to your email delivery success rate. Securing a dedicated IP is an important decision and usually connected to the volume of emails your marketing program requires. If you send more than three campaigns per week with volumes greater than 5,000 emails per campaign to different ISP’s, a dedicated IP address might be for you.
High volume email marketing programs require automated system to spread out the amount of emails over multiple IP addresses to keep data flowing smoothly.
Couple of factors determining your reputation are email volume and frequency, if you send low volume campaigns infrequently you probably are well served by a shared IP group.
If you see a decrease in open and conversion rates, and an increase in bounced emails, then you may want to consider securing a dedicated IP address.
Sharing IPs gives you the opportunity to pair up with other email marketing programs and establish enough volume, and frequency to have good results. That is if everyone is following the best email marketing practices.