What happens if you don't get a "cut loss/close the deal signal" if it goes against you...lets say 100pips or 200 pips...? well, little overdone, but what I mean is:
You should define how much are you willing to risk...and if not exact target, then at least estimated. You should know how much to trade for.
One cannot define what kind of money management to apply to his/her trading style until s/he has got test period of the system. Even if its fully automated system, r:r ratio should be one of the filters (just as vikingtraider suggested) to choose whether to trade or not specific signal.
If you have a very volatile trading (for ex.) on Euro, lets say its in a range of 200 pips for last week or so, and you get a buy signal (even a very strong one) very close to upper border of the range - what you do? will you trade the signal? You know that there was a very volatile trading recently, and the price may bounce back from that upper border just like it did during last week...what you do? will you follow the signal? on the one hand, you got a buy signal, on the other hand you know your first target (level) is very close to current price (lets say 20 pips), and the range was 200 pips, so the level where the price bounced back from recently (the recent strong support area) is 180 pips away...will you trade?
if the buy signal occurs near the lower border of the range (pattern), than it is a good trade, because stop may be put below the range border...
if you wait for signal to give you exit signal when you are in trade already...woow, man it is way too dangerous approach. So what you suggest? not setting the stop order? is that what you say?
You should define the stop and target before the trade, and it REALLY is best for trader ratio to be >1. Sure, during the trade, you may get an exit signal (cut losses or take profits before estimated stop or target), but initially those levels should be at least estimated.
Why >1? I think this is well explained by mishak, I also added some comments in "part 2" of this post (see link in mishaks' post).
I don't believe there are many traders having 100% of winning trades. I doubt there are many with 80%. I believe 60% is pretty good, but it also depends what is the avg gain in those 60% winners and what is the avg loss in rest 40% losing trades. Based on this and some more data (which can be obtained only after test of system - and preferably on real account), one can set filter on which trades to take when there is a signal, and which should be passes.
Just my 2 c,
Rezo