I’ve discussed this in the past, but it’s a topic that’s worth revisiting. There’s always a debate whenever a new version of an operating system comes out, about whether you should do a clean install or upgrade. If you’re running Windows, there’s a cost factor involved (as the upgrade disc is *usually cheaper* than a full retail disc). But if you’re running Linux, the cost is the same regardless of which way you go. Plus in Linux, depending on the distribution, you may not even need a disc, as there is an upgrade manager available to handle the download and upgrade process for you.
All things being equal, it’s better to do a complete clean installation, and then reinstall all of your applications and settings. Of course you should back up everything that you want to keep before doing this (as it will wipe everything out). In Linux, you also have the option of separating your /home directories from everything else (putting it in a separate partition). This helps to keep everything safe, and also allows you to switch between distributions without losing your data.
The reason that I, and a lot of others, advocate doing a clean installation vs. an upgrade is simple. If you’re building a new house, you start with a solid new foundation–not the old foundation that might have cracks and weak spots in it. The same thing goes for your computer. Start with a fresh installation of the operating system plus updates, and then reinstall your applications. That way everything is solid, and any misconfigurations or other bugs are not there. You can always tweak things to suit your needs later.
One other reason that a clean installation is better than an upgrade is if some of your installed programs aren’t compatible with the version you’re switching to, it could cause problems (or worse a non-booting system) during the upgrade process. By doing the clean install, you know that everything is compatible, and you’re able to choose what applications you want to install (or find alternatives for incompatible ones).
Also in some cases, you won’t have a choice. Windows Home Server (while it was available) went through a change in architecture (from 32-bit to 64-bit), so there was no upgrade path. Amahi Home Server goes through this with every release. There are no supported upgrade paths, although it *might* be possible to do it. As technologies change, architectures will be dropped. Eventually you won’t be able to install a 32-bit version at all–because the number of older computers will be small enough that it won’t be worth the trouble of spinning a version for them. In the future, the same will happen with 64-bit versions, or even versions for desktop computers.
In the past, upgrading because you had a lot of files, because you didn’t have the installers for your programs, or other reasons were valid arguments. Now with the advent of online storage, and hard drives in the Terabyte ranges, these arguments don’t really hold water. Plus you can find most installers online (especially if you downloaded them originally).
If you have opinions on why upgrading is better than a clean installation, please leave a comment about them. I’ll edit this post with the best ones (especially the ones that are hardest to debunk).