Ok, thanks guys...

I think the main point to take away from this thread is that if you are just doing testing from devel/testing you are always going to be able to recover the device if you brick it.

If you start playing around with the bios and other special case stuff, then you could find yourself in hot water - but most of these cases can be fixed, though either expensive and/or difficult.

@mmurfin87 - you mentioned software here if deleted or corrupted can ruin your system, do you have any examples of these and are we likely to run into this type of software from the repos......