Your question is virtually open ended. Which kind of doctoral degree you are preparing to read? If you are working in science and technology field, e.g. in research and development in electronic engineering. A PhD may be useful. If you are a lawyer, you can study part-time for a JSD. If you are a business executive, you can study part-time for a DBA. Likewise if your are a teacher, you can study part-time for a Doctor of Education, Doctor of Psychology etc. Most university professors do not have actual or professional working experience. For example, if you surf to the HKUST Accounting Dept website, you can see that all their Professors in accounting have no working experience in the accounting field. However, many "applied type" universities, e.g. PolyU insist their teaching staff should have sufficient working experience and a PhD. So if you wanna to change field and teach at university, why not go ahead to study a PhD. A professor with a PhD + 10 years working experience is very very rare. It is very easy to get a job from a university, in particular in accountancy department. However, if you were in some rare and funny industries and prepare to study a PhD in strange area, there is no guarantee.