HUMIDITY
If you keep the spider too dry it can get problems when its time to molt especially if its a rainforest species. Think of the habitate the spider originates from. The rainforest of South America or a dry african savanna? If you find your spider frequently sits over the waterdish its a clear sign you keeping it too dry and the spider tries to moisten the booklungs over the dish. Increase the humidity by pouring tepid water direct onto the substrate. On the other hand, if its too moist in the cage, the spider can develope spots of mould on the body and even legs can fall off as a result. Keep rainforest species in approx 80-90%, temperate living species 70-75% and arid semidesert living species 60% and below