upgrading & (re)installing

ok, to straighten out the confusion...

ubuntu only officially supports upgrading between consecutive versions. 

to move from 6.10 to, the latest, 7.10 you have two options:
1. "upgrade" from 6.10 to 7.04 and then upgrade from 7.04 to 7.10
2. "install" 7.10 over 6.10 where /home will be preserved but /etc won't

ubuntu does not officially support "apt-get dist-upgrade" to upgrade to a later version
(whether the next incremental version or not).  ubuntu only officially supports using update
manager (http://www.ubuntu.com/getubuntu/upgrading) to perform an upgrade.

i figure the reason is insufficient testing of upgrades.  debian puts a lot of emphasis on
upgrading between stable releases, but that only happens every year or two (overlooking sarge
;-) and is only expected to be between consecutive stable releases.  that's relatively easy as
compared to testing the upgrade process to the current ubuntu release from every currently
supported version (usually 3 versions supported concurrently with the last one being dropped
about the time a new one is released) and repeating this every 6 months.

the feature of the installer to install a new arbitrary version of ubuntu while preserving
/home (which on ubuntu by default is on the same partition as everything else) is appreciated.
ubuntu works well out-of-the-box for the average desktop user, so reinstalling ubuntu is
generally painless as there's little (re)configuring required.  so instead of spending the
time & bandwidth upgrading twice to get from 6.10 to 7.10 (or three times if you hold out a
month or so for 8.04), you can just install the version you want over the top and it won't
trash your user-specific configuration & data.

i'm curious if ubuntu is going to support upgrading between LTS releases (6.06 to 8.04) or if
the upgrade process will remain unchanged (6.06 -> 6.10 -> 7.04 -> 7.10 -> 8.04, whew!).  i
figure the main user of LTS releases are businesses/corporations, where it's currently
standard practice with windows to just refresh/reimage/reinstall the computer and manually
preserve/copy the user's data & config, so maybe ubuntu/canonical isn't going to put any
effort into insuring a smooth easy upgrade between LTS releases (though windows does ;-).

i have a desktop running 7.04 (the latest version available when i built it last summer) and
i'll probably install 8.04 from scratch to put everything on lvm and create a logical volume
for /home (if it's not already that way; can't remember).  after that i'll "install" LTS
releases to avoid the pain of multiple upgrades and as ubuntu has required very little
tweaking after installation (and the user data & config should be safe on the separate logical
volume for /home).