I tend to side with those who believe hard targets create more problems than they solve. Markets are fluid and dynamic. You cannot bend the will of the market to allow you to hit a specific profit target consistently IMHO. To try to force the market and/or stay with a position longer than you might otherwise to get to a certain profit target when it just isn�t there that day or hour or minute, will cost you money in the long run, whatever it is.
While I would certainly advocate doing what helps you make the most money irregardless of what anyone tells you, I personally would recommend taking what the markets allow, push when the odds are in your favor, be more conservative when they aren�t and concentrate on your risk control. If you concentrate on limiting risk first and taking just what the market will give with your given strategy in your current time frame, over time, I think you will be very happy with your results. To artificially limit your profit potential when you have to best of it or are in the groove, will make it harder to reach the next level IMHO. Because you will lose more than you plan to on occasion or when you are out of sync with the market flow because you didn�t reduce your size recognizing this, or worse, not even notice you were a bit out of the flow.
If it is a big trend day and assuming that is your strength, why you would limit your gain when if you take advantage of conditions can greatly increase your profits, especially over the long run, i.e. your year or career. To cut those potential profits short is very limiting IMHO.
Another good reason not to focus on your daily number to hard is because there are too many variables to allow you to be successful which may hurt your confidence in the short run (a day), which is very important. A trader needs confidence in himself and his methods or he/she will breakdown mentally or not follow his rules when he needs both the most. If you are best in trending markets (or whatever your strong suit is) and it is not trending today, you cannot press to reach a daily goal or you will suffer the consequences (and then blame something else probably). Now a weekly or even better, monthly idea of how much you can aim for will allow you the best of both worlds. It would allow you to keep a trend of your performance over a time frame where the inevitable good and bad luck and good and bad connection with the flow of the market should even itself out much more so than a daily goal can. Take what the market gives you daily and weekly, then monthly track your performance. I bet it helps you.
Good trading
BM