I water twice a week for the most part. I have a greenhouse and adjust each plants needs by the potting medium and its location relative to the two circulation fans that run 24x7. But I also watch each plant's health and adjust accordingly, mostly by what I see happing with the roots. Healthy roots = happy orchid. But in the end I'm always making adjustments. Like right now the humidity runs high so I'm conscience of my phals so I don't get crown rot.