What are the advantages of Ubuntu flavours ?

So I know they have a different Desktop Environment and a new look

But I am not sure, How they differ from installing the desktop on Ubuntu itself?

eg:- sudo apt install kubuntu-desktop or sudo apt install kde-desktop or sudo apt install kubuntu-desktop^ or sudo apt install kde-standard

All the above commands install the KDE Plasma desktop environment (there are differences between commands (some are to download minimal, some are for full KDE)

So, how does installing a desktop different from installing flavour

As installing sudo apt install kde-full or sudo apt install kubuntu-desktop^ installs all the packages which kubuntu has by default.

Also, We can always purge useless packages:-

sudo apt purge ubuntu-desktop
# Deletes ubuntu default desktop environment

sudo apt purge kde-desktop
# purge kde plasma desktop environment

sudo apt purge kde-*
# remove kde apps 

#### warning above commands are only for reference, don't run them, they can destroy everything (depends)

Also, guiverc mentioned in this post (answer to my question) that lubuntu flavour don't come with a lot of packages/apps/drivers

So installing lubuntu/kubuntu itself are the same as installing their desktops as The amount of ram usage also decreases when we switch desktops eg:- Lubuntu uses almost 200-900 MB of RAM and lubuntu-desktop also uses the same memory

Also in vanilla ubuntu we have a lot of apps and drivers (which we can always get rid of) So isn't it better ?

_{I don't mind using some storage/internet}

So why it is recommended to use ubuntu flavour instead of several desktop environments?

Can anybody correct me? Or am I correct?

_{I don't mind using some storage/internet}

Question in short - How ubuntu flavours are better than installing a new desktop environment on Vanilla Ubuntu

How ubuntu flavours are better than installing a new desktop environment on Vanilla Ubuntu

Fundamentally: not. One could perfectly transition an Ubuntu installation to say a Kubuntu installation. You would install say kubuntu-desktop on a default Ubuntu install, then would need to "chirugically" remove any packages that come with ubuntu-desktop but are not needed for Kubuntu.

Practically: yes. The latter step is the problem. It will be very difficult to granularly remove any packages of the initial Ubuntu desktop that are still there, but that would not have been installed with Kubuntu. One could find out all this looking at the installed packages and their dependencies, but that would mean sifting manually through thousands of packages.

A note:

sudo apt purge ubuntu-desktop
# Deletes ubuntu default desktop environment

Not true. It doesn't. It only removes a tiny metapackage listing all components deemed essential for an Ubuntu desktop. The main packages are marked as "manually installed" and will not subsequently be removed by an autoremove.

I'm a lover of multiple DEsktops on my machine; but it does come with costs.

Like everything in life, there are pros & cons to every decision, and multiple DEs works for me; but it's not something I'd recommend for everyone (due to complexities & costs...)

The amount of RAM used by the desktop when nothing is running doesn't mean it's the most efficient when apps are added; your choice of DE may not share libraries/toolkits with the app you're using, meaning multiple libraries/toolkits need to co-exist in RAM wasting resources.

I still use x86 laptops with only 1GB of RAM, on those devices (with such limited RAM) I'm very careful with what I run so the box remains somewhat fast.

I don't worry about disk space (it has more than enough & most my files are on network shares anyway) but RAM is tight.

With Ubuntu 18.04 LTS I have LXDE (lubuntu-desktop) & XFCE (xubuntu-desktop) installed. In that release there isn't much different between them (LXDE is GTK2, but XFCE is 18.04 was still part-GTK2 & part-GTK3), so differences between GTK3 apps may not differ.

When using 18.10 (or 19.04) which was available for i386; Lubuntu had switched to Qt5, and XFCE had continued it's porting to GTK3 so the difference was significant. If I looked at RAM used with the OS idle; Lubuntu & LXQt won hands down, but if running a GTK3 app; the LXQt desktop used by Lubuntu had Qt5 libs available, but the running of a GTK3 app required GTK3 apps (that did the same thing as the Qt5 apps) to also co-exist in RAM; an issue that may not occur if I logged out & switched to using Xubuntu/XFCE.

fyi: the box I'm using as example runs 18.04; as 18.10 & 19.04 are EOL so 18.04 is the last Ubuntu choice for i386.

The problem is every apps requirements (depends) vary; so what might be a minimal resource hit with one app, may be more significant with a different app. With more RAM, you need worry less about this; I don't worry if my box has 5GB or more of RAM; but do consider things like this somewhat if 4GB or less & greatly if RAM is 2GB or less.

Multiple DEs installed

• use more disk space
• more bandwidth in upgrades (more packages to upgrade)
• more complex menus (multiple apps that do the same thing; one for each desktop usually)
• if too many DEs (4+ in my experience) are installed; they can create conflicts that sour the experience somewhat; one reason why it's not recommended for newbies