Current price discovery is not really healthy or sustainable. I would hate to see bitcoin top at 35k and spend the next two years doing nothing. If the trend continues with parabolic advancement, I would likely start taking profit at 30k-35k. Again, this is the immediate price action (within 2 weeks). If bitcoin flash crash 30%, I would be more than happy to let that happen and do nothing.
Comment:
On second thought, after looking at Tesla's three parabolic bull run this year (which likely to continue next year), I think the whole idea of "top" after one parabolic run (like 2017) seems invalid. Still, risk management is the key.