In general it is always great to use stop losses while trading but not always.

Some years ago I was big into trading warrants on traditional exchanges and I got a very bad experience with stop losses. On warrants there is most of the time a market maker that sets a price for sale and for buy. Since the price of a warrant is defined by the underlying stock or commodity, the market maker adapts the prices constantly. I believed that a stop loss would protect me from big drop in prices on these warrants. The problem is that these stop loss orders are only executed when there is a transaction on the market.

There was a huge drop in the underlying asset and the warrant lost about 90% of its value. My stop loss was set at 10% under the price of the previous day but it was not executed because there was no transaction on the market. Before using stop loss orders I would always make sure that the market is liquid and that there are transactions, otherwise the stop loss won't work.