Re: So when should you buy in. My thoughts from a long term bear.
What if bitcoin stays low like this forever and never goes back to ATH? 
There are only two alternatives for BTC futur :
-moon if it's a success
-Mariana trench otherwise
I was writing exactly what Seldar just said.
Let s think: there will only be 21 million BTC. At $20 each, market cap would be mere $420 million. Way to few to provide adequate market depth or to allow big sum business. At $10K USD per BTC we would have $210 billion. And $2.1 trillion at $100K each. Now that would be capable to sustain BTC as gross payment media.
So that s it. BTC MUST be a full success AND moon price to survive. Otherwise it will simply die. iMHO.