Should you be doing a phD?

This question about whether doing a phD is becoming commonly asked among my graduates. I suppose the trend nowadays is going beyond even a basic degree to a postgraduate degree.

Some of my thoughts:

1. Is a postgraduate degree useful to your career path? For Singapore, the 2 major sectors that employ phD holders are:
1. Academia - are you thinking of teaching in one of the tertiary institutions? These include the polytechnics as they are increasingly offering degree programmes via tie-ups with overseas universities e.g. Food, Optometry degrees in SP
2. Research - All Astar research institutions generally require their scientists to have at least a phD. There are also research labs in certain companies e.g.  pharmaceutical, food which may or  may not need a phD holder.
   
2. Naturally, the sum total of job offers from the above 2 sectors does not add up significantly compared to the number of degree holders employed in the Singapore market. If you feel that being a chemist/ engineer/ sales agent/ manager is your calling, a phD probably is extraneous.
   
3. Time and money
   Can you afford to spend 4-5 years in a phD with minimal pay (I mean allowance)? Even with a university scholarship, don't expect to be paid a degree holder's pay. If you have a family to support, this can really be a bummer. (There are however certain companies which offer full pay to their employees while these employees engage in a full time phD. You can approach me to find out more about these companies :-)
   
   If you decide to take the part time route while holding a full time job, good luck. I am not saying that it cannot be done but you will need to ease off on your family and other committments. One more kid coming along, tough luck.
   
   Certain phD supervisors expect their part time students to work like full time students, meaning you are supposed to work till 11p.m. every day and come back on weekends and public holidays. Are you prepared for that? Do you want to forgo your weekly shopping, pubbing and clubbing (not that I am a big fan of these activities)?