I do used to buy coins when the price is fell back ward and there is a serious dumb. The coins must have fell back world to said 30% and sell when it is in positive of 10%. I have never make a serious loses but make a reasonable profit. I have decided to follow this ageing principle of buying low and sell high.
I used to apply the same strategy but then I made a huge loss by the way. I bought sonm tokens continuously while it's dumping from 3.5k satoshi to 2k satoshi. Can you imagine that?
It's not right every time.