Currently, the "How many and how big?" section contains redundant repeated information of dubious factual accuracy: "For instance, if there are lots of users, then it is advised to have /home/ separate as it increases security and makes backups easier. [...] Game servers will have a separate /opt/ as most gaming servers are installed there. The reason is similar for /home/: security and backups." Right below this text is an explanation for why it is a good or a bad idea to have a separate partition for a given directory, with points both for and against having one, that explains the topic well. So the lines I pasted above are not needed and just oversimplify (and duplicate) information. In addition, whether or not something should be made a separate partition is also filesystem-specific. For instance, Btrfs uses subvolumes, which have the mentioned security benefits of a full partition, without the drawbacks of having to statically allocate space to it or use an initramfs. In addition, mentioning /usr as a separate partition is a bad idea to begin with, as it risks a situation where /usr/portage gets desynced from /var/lib/portage. My suggestion would be for something like this to replace the very first paragraph: "The number of partitions is highly dependent on the environment and chosen filesystems. At minimum, the system should have partitions for swap, / and (on UEFI systems) EFI SYSTEM. Sometimes it makes sense to separate some more directories into their own partitions. In most situations, the / partition is to be kept big: not only will it contain the majority of applications, the Portage tree alone takes around 500 MBs excluding the various sources that are stored in it." In addition, the pros and cons of splitting a partition at the moment are presented in an inconsistent manner. Either both pros and cons should be bullet lists, or both should be plain text paragraphs. Finally, the sentence "often require the administrator to boot with an initramfs to mount the partition before other boot scripts start." should be replaced with init-system-neutral terminology, such as: "often require the administrator to boot with an initramfs to mount the partition before the system boot can proceed."
please use the "discussion" tab for suggestions on the handbook wiki page itself.