Honestly I'd like to see new traders experienced all things that a trader must avoid because that will be their key foundation for much stronger and wiser decision in the future. Those errors, mistakes, too much emotion etc. that they will experienced on the way will be the things that they will now avoid or control in the future because they already used to it.
In such cases, that after a "long time trading" and that trader still not learned and experience continous losses then it might be the right time to change course as trading is suitable to them.
I couldnt agree more, in that way theyll be able to come up with strategies on their own a long the way. Getting more experience and the more new traders exposed to trading they can learn a lot and make them better traders over time. Mistakes are inevitable even those experienced traders still make mistakes from time to time and I think its normal whats important is they have learned from that mistake and make sure to do something not to make the same mistake twice.
It all comes with practice. You learn things about trading by actually doing it. So it is important to know and understand about all those things which are not considered risk free for newbies. You may loose or win money but the most important lesson I have learnt is staying emotionally sound and good. This keeps you the king of the trading.