A lot of our customers believe that the proxies required should be from different class-B, which is xx.B.xx.xx. Otherwise, they will be quickly banned by the website or software they have been used for. For example, IPs 188.8.131.52 and 184.108.40.206 are from the same Class B, which is 111.222.xx.xx. According to common belief, if one of these IPs is banned, the other one will be banned simultaneously.
In reality, based on many years of our experience providing proxies for different purposes, most often what really matters is the class C, which is xx.xx.C.xx. For example, IPs 220.127.116.11 and 18.104.22.168 are from different classes C, that are 111.222.33.xx and 111.222.34.xx.
We can provide a lot of different class-C ranges for various purposes. Usually this is more than enough to minimise proxy losses.