Confusion about when it's my navigation, and when it's ATC

In article ,
Mxsmanic wrote:

Pixel Dent writes:

I think I read this section before; this paragraph sounds familiar. I
always get instructions to "maintain," though. What's the phraseology
when I get a block of altitudes? Or does it even happen with
frequency in real life? How do I request it (or do I even need to
request it)?

In general (i.e. I'm sure someone will come up with an exception), you
won't get things like cruise clearances, VFR on Top Clearances, or block
altitudes unless you specifically ask for them. 99% of the time ATC
gives you an altitude and expects you to stay there until they tell you
otherwise.

That doesn't mean you can't ask for a descent when your FMS tells you it
wants to start down, but there are a number of reasons you may not get
it. There may be conflicting traffic below you or the controlling
authority for the area you are in may have letters of agreement with the
surrounding areas that specify what altitude flights heading in various
directions or to various destinations must be at. In addition sometimes
the controller you're talking to doesn't control the altitude you want
to head down to. For a given ground position there may be three
different controllers handling different altitude blocks and your guy
may not have time to coordinate or even be allowed to descend flights
into the area below you.