Brake shudder

Perkuleez

Ok first of all, sorry for posting on this again I know its been discussed many times on this forum however I'm getting conflicting information.

So basically the issue is at freeway speeds 60-80mph and doing moderate braking, there seems to be a shudder. This is noticeable just about everytime I exit the freeway. I also notice this when doing spirited driving around the mountains. During this spirited mountain driving I notice the problem becomes progressively worse. ((again I'm doing what I would still consider moderate braking (no brake fade, when I get out I don't smell brakes)

So on to the question as I'm not sure exactly what the issue is. I've read everything from it being a warped rotor, deposites on the rotor from the pad, air bubbles in the brake fluid, abs malfunctioning, (the list goes on). So is there a definitive logical way we can go about figuring out which of those if any is the issue? Some light on this would be greatly appreciated.