The Harbinger and the Fountain
You initiate the Sight and make an Assessment attempt using Resolve or Willpower against a difficulty that I set, usually defaulting to +3. Depending on how well you succeed you will gain information, possibly in the form of an aspect, that you can use. If you fail the roll you take stress equal to the failure in shifts and don’t see what you need to. Once you make a roll you have the information and can then turn off your sight at will or, if you want to probe deeper, may continue to make assessment actions until you are ready to stop or your brain fries.I think we should differentiate the Sight from when you project astrally. Projecting will allow you to see the world around you as if you were walking or flying. If you decide to flip your sight on you travel to the spirit world and can perceive spirits. Because you are in the other place and time works differently you don’t have to roll mental defense every round, but if there is something you are trying to figure out (where a building would be in the real world, for example) you roll and take stress normally. If you let the spirit world wash over you it is relatively gentle but if you try to impose sense on it it will bite at you.