You can rack it if you want to but they say there's really no reason unless you are dry hopping or have another batch lined up for your primary. You can't depend on bubbles one way or the other. The only way to know for sure is to take a hydrometer sample. Some people go by 1-2-3. 1 week primary, 2 week secondary, 3 week bottles. I've only done 3 batches and am going by 2-2-3-2. 2 week prim, 2 week sec, 3 week bottle, 2 week fridge. After 2 weeks I check the gravity. Check it again and if its the same I rack it to my secondary to dry hop and free up the primary.