Arguably, there is no one best answer for this question. Different people will have different motives/drives in choosing to do a PhD. While doing a PhD is just of many things in one individual's life, it could be everything for another person. I belong to this latter cohort: once, doing a PhD was everything to me. And of course, the PhD in fact has offered me everything too. Therefore, what follows is just my experience on why I did a PhD
and what it offered me. I hope this account will provide you with some idea as to what could be expected in doing it.
I wanted to do a PhD because I was then an academic, a lecturer who had just completed his MBA. I joined the Faculty of Management Studies and Commerce at the University of Sri Jayewardenapura - Sri Lanka, in 2004 as a probationary lecturer. There, doing a masters degree was the major requirement for getting confirmation of my post. To that end, I managed to complete an MBA, and did so very well, in a prestigious institute called the Postgraduate Institute of Management (PIM), attached to the University of Sri Jayewardenapura. During this time in particular, but really since my childhood, I fantasised about the idea of going to a foreign country such as Japan or US to undertake my higher studies.
However, this dream of doing my higher education overseas was not easily possible in my case: the major constrain was money. I anticipated this constrain well in advance. I have heard about, and known, many who have gone overseas to do their PhDs but I did not get much support or guidance as to how I could do a PhD. However, I came to learn that one could win a scholarship, and that one does need to self-fund a PhD. I gathered information on what it takes to apply for a PhD and began to prepare myself. I knew that the most important thing of all is one's academic ability, how current one's knowledge is. I gathered that there must be a sound sophisticated research proposal for a novel idea of research which would generate new knowledge, a research idea that uses current knowledge in combination with the dominant work in the field. That's when I realised the importance of reading.
Now, if you are not a native English speaker and are from the UK or Europe for example, you will find it very difficult to keep up with current knowledge. I remember, in the libraries I used to frequent, there was hardly any books that were new. You would be lucky to find an international book published during the last decade. Our libraries mostly used to get books as donations, through the sources such as British Council, and hence are not the latest books to be published in the world. I remember, then, my monthly salary was nearly the cost of single a book on Amazon. So, you can imagine how hard the quest to keep up with cutting edge knowledge is going to get. I must say, the University system in Sri Lanka has developed greatly since then, but this could still be the reality in academia in most Third World countries. One could argue, you do not need books, but journal articles can provide new knowledge. Yet, my experience then was that most local Universities did not have access to top journals. We should also be cautious not to use the content freely available on internet, such as Google, or Wiki as they are not so reliable. This means that keeping up with new knowledge is one of the biggest constraints for the Third World aspiring academics. One reflexive strategy I used was to get in touch with one or two friends who were studying in the UK and Japan who had access to journals, to request their help with this.
From the early days I aspired to gain independence in life (emancipation, one could critically say?).