As I type, the scent of furniture polish fills the room.

Before sitting down to write I cleaned my desk, not just flipping the duster around the books and lamp as I usually do, as if they were bolted in place, but clearing the surface and attacking the grime with what can only be described as gusto. Before the day's work had even begun, two of my new year's resolutions had thus been upheld: waging a weekly war on dust, and burning up more calories.

There was a time when I squirmed if asked what resolutions I'd made for the coming year. Surely this was a childish game that adults only pretended to play, knowing full-well that they would relapse within the month, as old habits crept back like weeds in a lawn, too deeply rooted ever to be budged.

Now, I take a less lofty position. Last Saturday, the roar of a sergeant-major broke the seaside calm where I live. Drilling his troops out on the park, our local fitness instructor's commands probably reached across the Forth into Fife. A man who has swallowed a foghorn, whose merest whisper could fill the Armadillo, he runs what my partner unkindly refers to as the fat club.

This was his first January class, and more than 100 devotees - almost all women - were sprinting, stretching and kangaroo boxing, keen to kickstart their 2014 health regime and undo the damage of the festive month. One curled up in agony with leg cramp, like a footballer craving attention, and some were constantly out of synch, like the child who's always given the triangle to play in the school orchestra, but each and every one was hell-bent on raising a sweat. How could you not be impressed? Had I been given new knees for Christmas, I'd have been out there too.

Making resolutions at the start of January is a terrible cliche, the mainstay of women's magazines and the low-grade radio phone in. Why does it matter whether you decide to improve yourself now, rather than in April or July?

Surely making decisions at this, the darkest and most enervating time of year, is self-defeating, guaranteed as it is that our willpower will falter. Who can cut back on carbs when Arctic conditions make one's lizard brain suggest that laying down a deeper layer of flab in case supplies run short is the sensible thing to do; that heading out into the night to an evening class, or to visit an elderly friend, is a bad idea, since one should stay indoors where it's warm and safe.

That ancient animal instinct is not wrong. Like bears and squirrels we are programmed to lie low and conserve our resources at this seasonal nadir. Yet no-one can deny that there is something powerful about the start of the year that makes us want to take ourselves in hand, even though the odds are stacked against us. The almost universal desire to become a better person is the human version of shedding an old skin and emerging brighter than before. It's the psychological equivalent of a spring clean. Whether the aim is to do more exercise, or cut down on alcohol, food and fags, or one's aspirations are more altruistic - to be less tetchy or do more for charity - the urge to make promises at new year is almost irresistible.

Those who think themselves beyond or above such things are either scarily self-disciplined or insufferably smug. Who among us wouldn't benefit from a bit of self-improvement? If I were to list my weak points, this page could not contain them. It's not that I think anyone should indulge in painful soul-searching or recrimination. But like daily recording angel Bridget Jones, or the writer Arnold Bennett, whose diary on December 31would tally how much he had earned and how many words he had written, there is something to be said for an end of year audit, and a set of fresh goals to balance the sheet.

Few of us will stick to our resolutions religiously; most will backslide a little, or a lot. But even if, or when, that happens, there is comfort in Samuel Beckett's timeless advice, to be remembered next January, and the one after that: "Ever tried. Ever failed. No matter. Try again. Fail again. Fail better."