When I was thinking about changing careers, I was given one piece of excellent and indispensable advice.
It's something I've handed on to a few other people since, it always seems to work, and so is probably time I wrote about.
For me, the time was 18 months ago, and it was a very big move.
I was contemplating leaving the security, renown and prestige of the BBC, to test myself as a teacher and trainer here in Cambridge.
I'm very glad I did, as the move was a renaissance for me, allowing me to learn new skills and do my little bit to help others in the world.
This week, for example, I gave a lecture to Cambridge University students about media careers.
It all went well, and quite a few were very grateful, saying I had given them new insights into how to get into journalism.
So, back to that brilliant piece of advice.
As it was such a big move, I did lots of research, asking people I respected - senior police officers, business executives, politicians etc. - for any tips.
The one which came back, time and again, was to try your new vocation before you leap into it.
It sounds obvious, but it's smart on three levels -
Firstly, you can be sure what you're getting into. How many times in life is the illusion far from the reality?
Secondly, you can test yourself out, to see if you've got the potential to make it in your new job.
Because I've seen this many times now, and there are few sadder experiences than someone desperately wanting to succeed in a career, but never having the ability to do so.
And so being continually passed over for the important roles, and thus continually getting upset and disheartened.
But the third point is perhaps the most important.
Trying before buying gives you the chance to set up some opportunities before you actually leave your current role.
Classically, it would be a full time job, but when you're opting for starting your own business and employing yourself, like me...
It gives you a chance to make contacts, set up a few lectures, workshops, and courses.
Ok, some of that will have to be unpaid to start with, while you prove yourself.
But do it well, and it's the way into some fascinating, and potentially lucrative work.
And wow, does it help on that big, scary, Day One in your New Life.
When instead of staring at a blank diary, to add to how unsettled you're feeling, you've got opportunities to work with.
I've had three careers now, and all still run contentedly, to more or less an extent, alongside each other.
Journalist, writer, teacher. What a wonderful combination. What's not to like? Lucky old me.
One more thing to mention on the changing careers front -
If you're bored in your current role, not appreciated, or just getting stale and seeking a change, I'd strongly recommend giving something different a try.
I won't do the finger wagging lecture thing (even if that's part of my new world!), but you've only got one life, and it's too beautiful a gift to waste.
Finally, life can be a lot safer as a teacher than a journalist.
Witness this photo I found of myself, from seven years ago -
It's a tad grainy, and yes, I know I look like Robocop...
But it's me doing my riot training for working in hostile environments with the BBC.
Cambridge, and the teaching and training lifestyle, has much to recommend it -
It's very far from hostile, and the chance of being bombarded with bricks, petrol bombs and bottles, is much less...
Unless, perhaps, I tell too many of my favoured cheesy jokes, and make a complete Horlicks of my next teaching assignment.