How often to water depends on:
- How fast the plant uses water compared to other kinds of plants. Desert cacti use much less water than leafy rain forest plants. Phalaenopsis use less water than Oncidiums or Vandas.
- How much water is in the pot at the end of watering.
- How fast water evaporates from the pot or transpires from the plant.
Water loss through evaporation or transpiration is faster at higher temperatures and lower relative humidity.
My Phals. are the orchids that need the least water, because they use less water than most other orchids. Perhaps I misunderstand. There aren't many plants that use less water than Phals. grown in a house. Perhaps Sansevieria or Haworthia. Most other succulents don't get enough light in a home.