Starting point:

• I currently do development for Dynamics Ax, Android and an occasional dabble with Wordpress and Python.
• Soon, I'll start a project involving setting up WP on Google Apps Engine.
• Everything is, and should continue to, run from the same PC (running Linux Mint).

Issue:

I'm afraid of botching/bogging down my setup due to tinkering/installing multiple runtimes/IDE's/SDK's/Services, so I was thinking of using multiple users, each purposed to handle the task at hand (web, Android etc) and making each user as inert as possible to one another.

What I need to know is the following:

• Is this a good/feasible practice? The second closest thing to this using remote desktops connections, either to computers or to VM's, which I'd rather avoid.
• What about switching users? Can it be made seamless?
• Anything else I should know?

Update and clarification regarding VM's and whatnot:

The reason I wish to avoid resorting to VM's is that I dislike the performance impact and sluggishness associated with it.
I also suspect it might add a layer of complexity I wish to avoid.

This answer by Wyatt is interesting but I think it's only partly suited for requirements (web development for example). Also, in reference to the point made about system wide installs, there is a level compromise I should accept as experessed by this for example.

This option suggested by 9000 is also enticing (more than VM's actually) and by no means do I intend to "Juggle" JVMs and whatnot, partly due to the reason mentioned before.

Regarding complexity, I agree and would consider what was said, only from my experience I tend to pollute my work environment with SDKs and runtimes I tried and discarded, which would occasionally leave leftovers which cause issues throught the session.

What I really want is a set of well defined, non virtualized sessions from which I can choose at my leisure and be mostly (to a reasonable extent) safe from affecting each session from the other. And what I'm really asking is if and how can this be done using user accounts.