As most Ubuntu users will know, Ubuntu 12.04 is a Long Term Support (LTS) release. As an LTS, Ubuntu 12.04 (Precise Pangolin), released on 26 April 2012, is scheduled to receive updates and support, for both the desktop and server versions, until October 2017. What many Ubuntu users may not know is that Ubuntu 12.04 will see maintenance releases over this period. The first of those, 12.04.1, is due on 16 August.
During its five years of life, Precise Pangolin is scheduled to receive three further maintenance releases: 12.04.2 on 7 February 2013, Ubuntu 12.04.3 in mid-2013 and Ubuntu 12.04.4 on 24 January 2014.
One of the most annoying aspects of installing modern software is the frequently drawn-out process of downloading and installing updates — updates that are replacing software elements installed earlier in the process, and therefore increasing the total install time. This is because a release install image freezes the software at a fixed point in time, after which the image rapidly becomes out-of-date. As a result, an install is often accompanied by a large number of updates, with the volume of updates getting larger as time passes.
With a long-lifetime LTS release, the update problem is exacerbated. A partial solution is to occasionally update the install image during the span of the product's lifetime. The Ubuntu maintenance releases are such updates, and new installations performed using a maintenance release get the benefit of fewer updates required as part of a fresh install. Users who installed early on in the life cycle, and regularly applied updates as they became available, don't need to worry about the maintenance releases because they already have the updates installed.
Since the majority of updates tend to appear during the early phase of a product's life cycle and the frequency of fresh installs falls, it makes sense to schedule maintenance releases to taper off towards end-of-life. With Ubuntu 12.04, all the planned maintenance releases are scheduled for the first two years of its five-year support lifetime.
If you're planning a fresh install of the current LTS version of Ubuntu you'll save on install time if you wait for the first maintenance release. If you're hungering for the next Ubuntu release, 12.10 (Quantal Quetzal), you don't have that long to wait — the first beta is due on 6 September and the final release on 18 October. I'll be reporting on 12.10 as its release draws nearer.