Pereskiopsis is a cacti. It can withstand drying out of the soil. With that said.... watering, fertilizing, humidity, heat... are all key and in different proportions depending on each other... so that is a learning process that is individual in nature to some extent. I find that Pereskiopsis can generally withstand overwatering much better than many cacti, but so too can Opuntia compressa. Pereskiopsis can also be pushed much harder with fertilizers organic or otherwise than many other cacti. To be honest, I tend to error on the side of overfeeding sometimes with my Trichocereus and Pereskiopsis both and unless your looking to grow show specimens there is not as much harm in it as there would be for other slower growing cacti or cacti grafted to these as stock plants.