Something that I think people don't consider enough is learning compression. That is, the more you trade, the faster you are likely to learn because the feedback loop is shorter.
So someone who places 3 trades per day on the M15 chart is going to have learned much more after one year than someone who places 1 trade per week on the D1 chart. That is not to say that the lower time-frame is actually a better (as in, more profitable) way of trading, but since we learn by doing, the higher frequency strategies will tend to 'educate' you faster than the low frequency strategies.
Of course, we are assuming that equal effort is put into each trade. Clearly, opening a dozen random positions each day will teach you very little.