How Big is Too Big?

[Fairorchids]

The Catt seems to be growing in all directions, but bulbs are spaced fairly tightly. You should look for a pot that gives you at least 1.1/2" additional space in all directions.

For the Oncid, it looks 'ready to be dividided' to me. Once you do, each piece should have one side with only older bulbs. Repot that side tightly against the pot, and give it a good 2" on the growth side.

Even if you do sacrifice some roots, plants this size should bounce back quickly.