Obtaining your PhD is essential for a scientific career, and without it you can forget about tenure or taken seriously in a scientific discussion. Not that you will be taken seriously when you have a PhD, but it does help. It is an important part of our educational system and I recommend it to anyone, although it depends on your future career whether it is really necessary, and in a lot of work environments people are unaware of the qualifications that come with a PhD. It should serve as proof that you are able to adhere to long-term goals, can write a substantial piece of work, are able to write logically coherent documents, know how to translate complex research in simpler terms, know your way around in scientific literature, are able to discuss it with peers, learn to speak in front of large audiences, perform research independently, among other things. These abilities are useful in most academic work environments but are not universally recognized, even though the basic skills for instance in writing an offering for a prospective customer are similar to writing a research proposal.When I did my PhD there was a slow transition to the anglosaxon trajectory for a PhD. Before the 90s, people would take their time getting their Master's (often more than 6 year) and then started a PhD at the same pace, often doing research in parallel with a paid job. This led to an average age of over 30 for a new doctor, in sharp contrast with for instance the british PhD's that coulkd have finished their PHD by the age of 23. In my time, the PhD trajectory was fit in 4 years and more organized into an educational program. Although the average time was still more than 5 years, I managed to do mine in 4 years which is long enough in my hands (the learning curve levels after 3 years anyway). One of the most important things is that you work towards articles and stay focussed on the necessary results.

Although not always an easy time, as most PhD candidates will agree, all-in-all it was a good experience and I did obtain most of the goals I mentioned above. Most of my research I could do independently, I started new lines of research, got to learn a lot of techniques, visited other international labs and conferences, managed to publish 4 articles and two additional chapters for my thesis, spoke in front of large audiences, got to teach etc. One of the most important things is the development of writing skills and having the patience to spend a sunbstantial amount of time revising and improving documents. Since anonymous peer-review will attack all inconsistencies (either logical or experimental) in a manuscript, it trained my to write logically coherent manuscripts.