I have searched the forum and scoured the instruction manuals, but so far cannot find anything about a "proper" shut-down procedure for my machine (a Rocket Giotto Evoluzione V2, i.e. HX and rotary pump).

Basically, should I be "flushing" all the tubes (steam/group/water) so that there is no residual pressure in the tubes and boiler, or should I keep them pressurized at shut-off?
Will one or the other result in longer component life? Or is there really no difference?

Thanks in advance!

Just turning it off is fine. Once every two to four weeks it is a good idea to flush out the water in the boiler to lower the mineral concentration that builds up from steaming before shutting down, but other than the normal cleaning chores (clear-water backflush, group gasket scrub, occasional shower screen removal, etc.) just turning it off is fine.

That's good to know -- thanks!

Does draining the boiler require using the drain plug/screw (if there is one), or is simply "refreshing" the water in the boiler by using the hot water tap/wand enough?

Using the tap should be sufficient. If you don't steam very often you might not need to flush as often. If you make americanos or use the tap for rinsing, that counts too.