Every week I receive assorted invitations to drink a cup of coffee with perfect strangers. Readers email to say that they are passing through London on business, and would like to pay me a visit at the office.

People get in touch wanting to bend my ear about books they have written or companies they are setting up. Students suggest meetings with a view to getting some free help with their work. And then there is the steady stream of misguided, overoptimistic twenty-somethings requesting coffee so that I can advise them on how to get into journalism.

You don’t need to be a journalist to be constantly canvassed in this way. Anyone can find anyone’s email; anyone can suggest a coffee. At any given moment of the business day, millions of mostly pointless coffees are being had as armies of idle business travellers, students and other chancers are filling up their schedules by clogging up the schedules of strangers.

In my case, there is nothing obvious to be gained from these encounters. I don’t have any jobs to give out, I have nothing terribly exciting to say to readers other than: “Hello, would you like to see our canteen?” I usually have no intention of writing about the book or business venture and I am not especially good at helping students with their work.

The rudest option

So how should I deal with these requests? To issue a blanket no is hard and mean. To say yes feels pleasantly accommodating at the time, but inevitably has you raging on the day and cursing yourself for having weakly acquiesced. That leaves not replying at all, which is the easiest – and rudest – option.

My strategy is to have no strategy. How I respond, or fail to respond, depends entirely on the mood in which the email catches me. The only people I almost always agree to meet are aspiring journalists who are either friends of my children, or the offspring of friends. This, of course, is nepotism. But it’s also human nature.

Last week I chanced on a better way of rationing time spent on strangers that is being used by Debbie Horovitch, a social media expert.

She makes everyone who approaches her fill in an application form on which they outline the questions they want answered, which allows her to weed out the most egregious time-wasters and decide who is worthy of meeting.

The beauty of this system is that it forces other people to do their homework. It gives you a scientific basis for saying yes or no. It is more polite and fairer than not replying at all.

The technique has so impressed Dorie Clark of Duke University that she has adopted it herself and written a blog post about it for Harvard Business Review called "Stop People from Wasting Your Time". It's fantastic, she says, because generally when you send people a form you never hear from them again.

There is a catch to this. Anyone who receives such a form will surely conclude you are a pompous, self-important stickler – which is presumably the main reason they scurry away.

There is a second catch, which is even bigger. I doubt if these application forms weed out the true time-wasters. There is a sad law in life that says the people most anxious to meet you – and these will surely be the ones who make sure they fill in the form adequately – are the very people who you are least anxious to spend any time with.

Chosen at whim

So I have come up with a better system. It is to submit to one brief meeting every week with one stranger, chosen at whim, granted perhaps to the supplicant whose email most tickles my fancy.

Now I think of it, the resulting coffee may not be so pointless after all. For a start, you never know which coffees will turn out to be useful and which won’t. I have often got great ideas from some of the most unlikely people.

Second, meeting young people who want to be journalists is almost certainly more useful to me than it is to them. It reminds me that I must keep on my toes and be eternally grateful to be fifty-something and not in my early 20s.

And best of all, I now discover that meeting readers may not be at all pointless either – in fact, it has just been scientifically proved to be the reverse. Last week I read about an interesting piece of research showing that cooks make tastier food when they can see who is going to eat it. If the chefs in the experiment could see their customers, the resulting meals were judged to be 10 per cent tastier.

I don’t see why the same should not be true for writers. If you think this column could have been 10 per cent smarter, funnier and more interesting, then you know what to blame – the fact that last week I had coffee with no strangers at all.

Copyright The Financial Times Limited 2014