[sandra]

I would repot it when you start seeing roots growing, especially Dends., before it flowers, not after. You can repot after flowering but the plant will acclimate faster if you do it while new roots and growth are sprouting.

I keep mine in a plastic pot though, there's no reason why you can't use clay, just preference is why. If you find that the plant is retaining more moisture than usual, if the bark is soggy and, if you know the plant's been in the same medium for 2 or more years, chances are, it needs repotting.