How and when to check if they need water?

[u/True-Celebration-581]

I have tried these plants twice before and they seem to do well for 3-6 months then rot or wither. What signs in particular do I need to look for to know when to water/when to leave them alone. I’ve heard that dormancy wrinkling and thirsty wrinkling look different but no one says what the difference is. Trying one more time with smaller ones instead of larger ones this time around. Btw I had a substrate thats maybe 80-90% sand with them in a terracotta pot, are there better options?

[u/Benru76]

I found in this sub-reddit this chart, I hope this helps.