The potting mix should be well draining enough for the water to run out of the bottom fairly fast after you pour it in, but hold enough water to keep your plants alive until the next watering.
I don't think yours is capable of drying out even in a couple days. It seem too hold to much water. More importantly it is lacking in good aeration. Tiny air pockets that provide you plant's roots with oxygen even after you water it. Your appears to be water logged. A good succulent potting mix should never look like mud.
I can give you a better answer if you add to you post what you put in your potting mix and that proportion. In my experience sand is never a good material to use. It tends to fill in all the little pore spaces that would normally exist, like clogging up your pumice's pores.
You get mud and sand and you create concrete. Wet sloppy concrete that once it dries if becomes hard as a rock. It also appears you use garden soil in your mix. If you did what type of soil is it? Does it have a lot of clay. If you added a clay based soil to sand you did create concrete.
The sizes of the matter you are using is too disproportional. You have some really large white pieces that serve no purpose if all the rest of the stuff is much smaller. All the small stuff will work its way to the bottom of the pot. Eventually you will not be able to see any soil. All you will see is the large white rock on top. You will have no idea when to water and when the soil is water logged. I really think we need to start over. I will help you.
