Do you know if the color change if you sweat or with the time?

Doesn't change. You can even take shower with it.

Can you wear it all the time and in the shower?

I wear mine 24/7 and have not had any issues with any of my Swarovski jewelry. I do TRY to avoid spraying perfume directly on it, and I take my earrings off weekly to clean them. I’ve had a pair of hoops with the crystals in them for 4 years and wore them 24/7, it wasn’t until the end of my 4th year that I started loosing some stones. Well worth the purchase considering. I’ve even worn them to the river, won’t do that again I almost lost one, but again it stands up to the elements. I’ll never purchase any other brand of jewelry again. I keep it classic so I’ll just repurchase something if it wears out. I recommend this brand especially if u buy from Amazon you can’t go wrong u can always return or exchange it… but I’ve never had to!