To start with I would like to say that both ideas of having a single career or to have multiple careers are good. Cause, for some people are easier to concentrate on one thing and work on it for all life, get successful in it and for other better to grow in a few different types of work.
For example, we I have a good friend Johnatan that into architecture from the young age and it’s the main course of his life, the man knows that it’s the only thing that he wants to do in his life, so his main goal is to achieve success in this occupation and he did it by hardworking and believe in himself. Same situation with my other friend, Jane that also want to an architect since she was a kid, she gets successful in this job too, but then she realized that her heart now belongs to computer science, so she decided to study it, even if its not with what she deals earlier.
Correspondingly I want to say that have a singe career isn’t an old fashion, we all have some goals and no one should have few careers cause it’s a trend for now. I want to add that sometimes it’s hard to achieve what we want in our life, sometimes we don’t have a choice and should have few ways of earning money to not be poor, because the case that we love don’t bring us enough money for living, but it doesn’t mean that it’s bad for us, maybe our successful future waits for us in another sector that we will love with time.
To summaries with all of this I want to say that for some people is enough to be successful in one thing, but other always want to achieve more in their lives or they need time to find they success in another place to achieve they’re happiness.