Originally Posted by
Thomas15
As a point of information, you can switch between challenges and not lose anything you have already acquired. So if you are going to do a ride with a lot of climbing change to the Everest Challenge, a flat route with a lot of miles use Ride California. Of the three challenges, the Everest is by far the most difficult but offers the best in-game reward. The California and Italy only require miles, the Everest only requires feet or meters of ascent.
I have read on zwift insider that you must complete the everest challenge for it to count before changing challenges. the climbing must be consecutive to count. so, switch challenges at your own risk, it would be a shame to have to start over.