Answer:
It can be very serious depending on the conditions of the break. If you have a non-union like I did it can take a long time. I had a long arm cast for 5 months and a wrist brace for 3 more months and I'm still not healed. The scaphoid is on of the slowest healing bones in the body and many times requires surgery with a pin, screw, bone graft, or a combination of a pin and a bone graft.
If you are lucky enough to catch the break early, it can simply be treated with a cast for up to 6 weeks. It all depends on the severity and conditions of your break.