Hi Hilty,
This is NOT a stupid question at all! In fact it concerns perhaps the most important and relevant principle in trading that one can possibly raise! It is at the very core of trading as a business. It is all about money management.
The key element in trading is recognise that a loss is NOT a mistake or a failure. It is an integral component of trading as a whole.
The central issue in your trading process is not your open position(s) at any one time, it is the overall growth in your capital balance. You cannot grow your capital without trading and some trades will always lose. The key is managing your risk and your capital such that overall your gains exceed these losses - that is the very nature of trading.
One could compare it with a shop. Shops gain from selling products with a mark-up. If they do not buy goods to sell, they will never make a profit. But they always lose something from damaged stock, customer returns, pilfering, unsold stock etc. But this is an integral part of the retail process and is manageable and, more importantly, calculated into the business plan upfront.
Does a retailer hang on to old stock in the hope that it can sell it “one day” in the future? No! it sells it off cheap and clears shelf space for new products that can earn profits!
Traders should think the same. You set up a trade because it meets your entry criteria. You already have a profit target in mind. But if it does not proceed as anticipated then there will come a point where the criteria for having initially entered the trade is now invalidated. The trade no longer meets your set of rules. That is the time to get out and wait for the next set up.
Managing and minimizing the damage from your losing positions is maybe far more important and effective than monitoring your gains. One of the most depressing situations in trading is to build up a profit through hard work and dedication over a period of weeks - only to see it wiped out in a few hours through a sudden move and no damage control in place.
One other serious problem with running losing positions is that they are “marked to market” on a real-time basis. In other words, as your position loss grows more money is locked out of your account equity to cover it. Eventually, if your equity is too little you will have to either keep adding more funds to it or it will be closed and the full loss realised and you account washed away. As a trader, this is a totally destructive scenario where one would be feeding a losing position for months with no opportunity to concentrate on trading!
Here is an example of what can go wrong. Around the start of this year there was a lot of hype about the EURUSD going to par. We were trading in the 1.0400’s. You could have justifiably sold a position here targeting par (red ring on the chart). This is the weekly chart showing what has happened since - ask yourself the question: What would have been better: to still be holding on to that short position nine months later and currently at 1.18 - 1.19 (which might take literally years to return to those levels, if ever, during your trading career) or to have cut the position once your entry criteria was nullified and taken a long position instead? Which of these two scenarios is “trading”?
Edited to add:
There is an interesting additional trading psychology point visible in this chart. If you had stubbornly continued to hold the original short position, you would see 2 dips a few months later. Now, you would interpret these with great relief as possibly reversals which at last were going to get you back to profit with your short. Whereas another trader, who had abandoned the short scenario weeks earlier would be eagerly looking at these as buying opportunites…your losing position is now distorting your analysis and blinding your vision of what is really going on…