In last couple of months I needed to create 3 new server + I have 2 couple of years old server and all 5 IP addresses that I received are blocked in many places due to which email from those IP are not getting sent. People are just misusing an IP, once they get blocked, so they just recreate new droplet and get new IP to play with.
And today I ran into a problem with one of my old server and had to destroy that server and need to do a fresh install. I wanted to keep my old IP as I have been using that IP from few years now. But I couldn't find any option to get that IP back, now I have to reassign new IP in many domains and places.