How often do you switch from up to down?

It can depend on the period, recently I have been rapid cycling (Having more than 4 episodes of Depression or Hypomania) and have experienced monthly episodes of both Depression and Hypomania, these symptoms often last weeks for me. In my case the Bipolar Depression can last for up to a couple of months where as the hypomania usually acts between 1-2 weeks.

What are the treatment options? 

Bipolar Disorder is most commonly treated with a combination of Medication and Psychological Therapies.

What can you do to help a friend with Bipolar Disorder?

There is no right answer to this question, each person is different. The most important thing is to let them know that you are there for them. 

For a more in depth answer I have written a blog post on this topic called 'What should I say?'

Can you tell when you are slipping into a Manic Or Depressive Episode? Or is it just hindsight?

Again this varies from person to person. For me I can't normally tell straight away whether I am having an episode, I find it a lot easier to tell that I am having a depressive episode than a Hypomanic Episode. I have. however, learnt to recognise the signs and therefore, I can start to recognise that I may be having an episode a lot more quickly than I may have previously.