Why is it that so many people including me don't like stop losses and yet the best people in the industry will tell you that you shouldn't trade without them. I came across this which I think might just solve the problem. https://www.youtube.com/watch?v=DW_EFskrCpc.
Depends what you are trading. If you have an illiquid stock and put a 10% stop on it with your broker, there is a good chance you will be stopped out. If you are trading FX then you should definatly have hard stops and in the case of the swiss franc to euro a couple of years ago it should have been a guarenteed stop.
A hard stop on stocks may not save you from a 20% - 50% profit warning price drop. In many cases the stock will open down passed your stop before your broker has a chance to initate it. Most brokers don't act on stops for the first 3 to 5 minutes after open and then they have to work through their stop list and find a buyer all while the price maybe dropping.
I haven't watched the video but its from IG so a lot of it will refer to index, FX and that type of leverage trading. So it may not all apply to stock investing.