This is just what works for me--now you must decide what will work for you.
Quite a few of the people on this forum will tell you that they repot as soon as possible after bringing a new orchid home. I like that advice
(especially if it is a rescue or has been in a big-box-store for a while.) It seems to be an excellent way of determining the shape the roots are in and you can also check out the medium and look for any insect/cultural damage. It seems to me that whenever I pull the moss away from a new plant, the roots are always yellow,mushy or completely dead,with just a hollow shell of what a root should be. So I prefer bark and what I use is Schultz's Orchid Mix. It works well for me
.
Good luck with yours.
Let us know what you decide will work in your growing conditions!