Some variegated yarn is dyed so that the outcome is very powerful. Others are very muted, and knit up almost tweedy. As a rule of thumb...I either use cables as the 'design element' or a variegated colorway as the design element...but rarely both within the same project.
I like dancejunky's two cabled mug cozies very much! The lighter variegated yarn played nicer with the cable. The green was okay too, mostly cuz that cable itself was powerful, occupying most of the cozie real estate
But using her green-variegated for a highly cabled sweater would be disastrous. You wouldn't know what to look at...the colors, or the intricacies of the cables.
Generally speaking...within the same project....
....they say that variegated yarns and cables fight for attention, and they both lose in the struggle.
Here is an example of a phone cozie that I knit up...using my own pattern...using a few yards of leftover yarn...see how the celtic cable is swallowed up by the variegated yarn? I knew full well this would happen...but I didn't care for this small little cozie...but I would never ever do this for a garment.
I threw in the celtic cable just for fun, last minute.
Here's another example...of a more subtle variegated yarn...I used this leftover yarn
for a cabled hat and scarf pattern. It worked out great!
Here's how the same yarn played out on the pullover...it quite seriously 'striped'...
and I'm not so sure I would have liked this yarn with cables. Cable interest usually
runs north-south...and the striping of this yarn definitely travels runs east-west. A fight.
Now (below) here is another scarf I knit up using leftover yarn...to wear with the cardigan.
It's a reversible brioche cabled scarf...and it looks much better with a solid yarn. Much.
See how the wavy north-south traveling cables are fighting with the east-west striping
of this yarn? Overall design rating...it's a disaster. But it suits what I wanted it for.
Another KH knitter had done this same brioche scarf in a Malabrigo semi-solid blue...and it was spectacular!