Orchids are really not difficult, and even the more temperamental ones can survive considerable neglect. Taking care of phals in particular is pretty easy. Unless you're housesitting for months, I'd say the only real danger is over-watering.

If it's happy where it is, don't move it. Don't over water. If it's in sphagnum (it probably is), water often enough to keep the sphagnum damp but not soaking. If in doubt, look at the roots - if there's green to them, the plant doesn't need watering. When you water, water the roots, not the leaves. Don't use freezing cold water or ice cubes.