2004 aztek wheel bearing

I have a 2000 aztek. I have replaced both front wheel bearings about a year ago. Now it sounds like another wheel bearing is going out again. My question is how do I know which one it is? When I turn the wheel to the right while driving the noise gets quiet, but when you turn to left it gets louder. I know they say you should change both wheel bearings at the same time, or in a pair, but they are just to damn expensive. Anyway thanks for the help in advance.

I'd say the rt wheel, you may feel some play in the hub that will point you to it also.