Question about using a polariser

I generally get what a polariser does, however I still have a couple of things I'm not 100% sure about

-does at polariser cut out reflections (from artificial lighting) in windows at night, when the inside is bright and the outside is dark?

-If i turn 90 degrees from angle of the sun's direction, turn polariser to max polarisation, does:
(a) if I move to a different location or angle, do I need to readjust the polariser again, to get max polarisation? (I believe to answer is no?)
(b) As time progress and the sun moves, do I need to change turn the polariser again, to get max polarisation? (I believe to answer is yes?)

I believe that the answer is yes and yes. The simplest way to confirm this is to use your LCD monitor as the light source. Pointing your camera directly at the LCD monitor, turn the polarizer till the screen goes black. Now change the angle of the camera while pointing to the LCD. You will note that you will have to turn the polarizer to block out the light again. The same principle would hold out in the open.

Yes and yes. Polarised light is angle specific so to achieve maximum reduction of reflections you will have to adjust your filter as your conditions change. You can see this yourself if you use a polariser on an ultra wide angle shot of a blue sky. The polarising effect will be greater on one side of the shot than on the other!

In answer to your first question, a polarizer can reduce reflections, especially through glass or water, but it doesn't necessarily completely eliminate them. In the instance your talking where it's dark outside and lit inside, you're definitely going to still get reflections off a window whether you're using a polarizer or not.

I think you have the general concept, but to fully understand the impact of a polarizer, you'll really just need to start using one. In some situations, the effects will be minimal to non-existant. . .in other situations, the difference a polarizer makes will be quite remarkable.