Traditionally if one want to use a hard drive (s)he has to partition it. “Since the dawn of time” the problem was – how. Partition cannot be easily moved around (moving 40 GiB chunk of data takes a long time), and it cannot be done while FS is mounted. What is worst repartitioning the disk while any of the partition is mounted prevents Linux from rereading the partition table – which basicly means that I have to do it from Live CD. While it is inconvenient for desktop user it is impossible for servers.
However I thought I do not need it. Well – what are my needs? 10 GiB for /usr for sure is enough, /var etc. on separate partitions with appropriate size. Rest for /home. As many times before live proved me wrong. Recently I started running of the space on /usr – and have plenty of space on /home – which was not only not-optimal but started stopping my system from working.