I think the main question doesn't change from the main bitcoin to any little small coin and anything in between. The proper time to trade has always been during either stagnant markets like we have right now or bull markets. If the price of any coin reaches to a point that last 30 days has been over 100%+ increase it is time to stop trading it for a while, at least watch it from afar before going back in.

If something has fallen a lot recently it is exactly the same, start watching from afar before trading. The best time to trade something is while its standing still without a move or when its just going up but hasn't gone up too much.