At one end of the spectrum we have debaters with the following opinion:
A) Awareness replace any Perception attribute checks.
If a check call for Perception (13) and you have Awareness; you use your Awareness step. Period. And since the talent allows you to spend Karma, you can.
On the opposite side of the debate we have this opinion:
B) Awareness is used strictly and only in the situations described in the talent entry:
- Spot hidden doors vaults/secret doors within range
Spot disguised or concealed characters within range
Find traps within range if you have the Disarm Trap talent
A few examples of how those two sides view Perception checks.
Since option A always use Awareness, I'll describe only what option B supporters prescribe.
- To check if you realize a main door key is missing from it's usual spot on the wall : Perception only
- To see if there is a guard doing the runs : Perception only
- To see that there is a guard hidden in an alcove : Awareness
- To find a secret door : Awareness
- To find a "normal" door in a completely dark room : Perception
- To notice that a crow is flying between the third level windows of two adjacent buildings precisely every 2 minutes : Perception