Yeah you are right, one's target can change from time due to some factors you just listed out and you are right no one should tell someone what his or her target should be because everyone has there own target, perspective and different financial strength. One's target changing from time to time should be in a way to balance everything to make for a good investment.
Is also best we make our goals strength in other to achieve what we desire and is also good for us to manage our finance very well, mistake is one thing that must happen to a newbie when it comes to investment but is best we learn from them and make sure we become better.
The hardest part of the problem is because people do not have a strategy so that the investment does not have the ability to increase because someone only relies on ordinary abilities. To carry out investment we need a target to achieve, for example if today we have half of a bitcoin then in the future it must increase according to the strategy we apply. If bitcoin is considered the best investment then steps must be taken because we will achieve it if we have a strategy. The ability to manage finances will determine success in investment and when you have that ability then I am sure the investment will be successful.
Everyone has made mistakes and no exception for people who already understand bitcoin, but these mistakes must be evaluated, so that when we walk we have a concept and have a strategy not to make the same mistakes. With mistakes we can learn to be stronger and investments will be carried out with caution.