ah Mounty, gotcha- wasn't sure if you had your PhD yet.
Now look. Let me tell you that it is the loneliest, most stressful, most joyless, most difficult, most bleak, most unassisted, most tiring thing you can do. You will also be poor, unless you get funding (I had the university's doctoral award, which paid my fees, but I have to work 3 days a week in a professional job to keep a roof over our heads). In order to get through all the above, you need to have an absolutely overwhelming passion for your subject. It needs to sustain you through at least 4 years and possibly more of pursuing the same idea through to the bitter, bitter end. I realise you will know all this, but it helps to reiterate. It will be with you from the moment you open your eyes in the morning, and will be there just as you go off to sleep. This is NOT an exaggeration!
There is no glamour in having a PhD - loads of people have them: no-one's impressed, and no-one cares. There'll be (I hope!) about a fortnight of me being excited that I get to put Dr on my credit cards, but I suspect that's about it.
The only thing that has sustained me is that mine is in literature & creative writing. Writing is all I have ever given one single solitary shit about. Everything else can go to hell except writing. It's obsessive. I despise my writing friends when they get snippets of success denied me, and when I get snippets of success they don't get, I gloat like Gollum with the One Ring. I realise this sounds deeply unattractive (all writers will know exactly what I'm talking about!) but I just want to emphasise that it really needs to be not an interest, but a passion: something that you would feel resentful and hollow about if you don't do.
As to lecturing and teaching - don't make me laugh till I vomit. Have you SEEN the jobs pages lately?! 2 years ago I didn't even have to look for teaching posts - I got a call from the head of dept asking me to do a term. Now, if you look for teaching posts in my subjct, there is nothing. This month 4 jobs came up, and they were all in Adelaide (who knew Australians could read and write ).
Of course all this changes with success, in any subject - if my book is published, and does well, I will get teaching, and might even get that fabled tenured post. But competition is fierce, and I'd quite happily stamp on my own granny for a job, so goodness knows what my competitors will do to me!
I'm basically doing what my supervisor did to me when I had my interview, which is do everything I can to put you off. If you still want to do it after that, then it's for you!
(There are wonderful things- the joy of research, the thrill of realising you've hit on something no-one else has noticed before, the satisfaction of using your brain until it can be used no more, meeting other like-minded folk, knowing that you're pursuing something fresh and new, the wonderful creative buzz of getting that brisk crisp paragraph out then looking at it and thinking, blimey, did I really write that?! I am a clever wee fucker and no mistake! But you can probably come up with the good stuff yourself!)
I hope this helps and suspect it doesn't.