Whether to use a stop loss or not is one of the big questions that are continually being discussed by traders, but there is actually no question at all about whether stop losses should be used or not.
Why to Use a Stop Loss
A stop loss is used to limit the amount of loss of a trade, by exiting the trade if the maximum acceptable loss is reached. For example, a long trade on the XYZ stock market at $25.02 might have a stop loss at $24.02, which would exit the trade if the XYZ stock market traded at $24.02.
Stop losses allow the trade to be exited promptly (i.e. as soon as the stop loss price is reached), and without any further involvement of the trader, which means that a stop loss can exit a trade even when the trader is unavailable (e.g. because of brokerage problems, etc.).
Why Not to Use a Stop Loss
Traders that do not use stop losses can always provide at least one reason (and usually several reasons) why they do not use stop losses, and they will usually argue vehemently against using stop losses, but the reasons are always incorrect. For example, traders that do not use stop losses often say that their stop losses are reached on purpose by larger traders, but this is incorrect, and it only means that they placed their stop loss incorrectly.
The Answer to the Non Existant Question
A stop loss should always be used for every trade, without any exceptions, and any trader that says otherwise is an amateur trader. Professional traders always use stop losses, either as a regular exit, an emergency exit, or both, and the professional traders are the ones making all the money.
