dendrobium repotting

[OrchidEye]

I'm pretty new still at taking care of my orchids, but have quickly become addicted to them.

I have two Dendrobium that both just lost their last bloom. one of them is laready growing some new roots and the other is starting to grow a new stalk.

So my question is would now be a good time to repot them?

If so what kind of medium should I use?

Thanks!