I already have all the models for the Ork army, and nothing has been purchased for the Tau army. So while I am purchasing and assembling models for the Tau army, I can start painting the Orks. When I get tired of painting the 30 Ork squads, paint some Tau for awhile.
I am in no rush to complete either of these armies, I just want some more armies to be able to play with. I personally enjoy the "collecting" of armies as much as I do the modeling/gaming of the hobby. I love to be able to just grab a different army off the shelf and throw down for a fun game. I get easily bored with just one army. The more the merrier.
So the next armies will be: