I'm fortunate to only have slight hazing, which I'll be addressing soon.
This was 100% the bulbs, I wasn't aware that they 'fade' but it was very noticeable when driving, when looking at the lights from outside they didn't seem dim or anything like that.
When driving in the dark you could tell that there wasn't any actual output. Really hard to describe, they're switched on and stood in front of the car looking at them nothing seems amiss, headlights look bright, but when in the car it was as though they'd lost about 50% of the light output, the road and shrubs etc weren't well lit. To the point I had to slow down to make safe progress.
With new bulbs it was instantly noticeable how much more light they produced, and how bad the old bulbs had become.