While many runners decide to change from cotton T-shirts to technical tops, or soccer shorts to proper running shorts, it is the footwear that is the big issue for most runners.
"The shoes are the big thing," says Damien McKeever, who runs specialist running and triathlon shop Amphibian King on the Dargle Road in Bray. "After they've done the half-marathon we find a lot of people look to change their shoes either because the ones they're using aren't working out or because they're just getting a bit wrecked.
"If they want to use new ones in the marathon itself then we look to get people into them before the sort of 18 or 20-mile long run that's usually done three or four weeks before the marathon. It means they get to test them in conditions close to those on the day itself and also because, ideally, new ones will have about 100km on the day of the race," he says.
About 50 per cent of those who come in unhappy with the shoes they've been wearing up to this point in their training each year, he reckons, have been using the wrong type and need to have their gait looked at so they can get a pair that suits them better. Wearing the wrong shoes can contribute to injuries and runners who don't know whether they might be over-pronators, neutral or supinators should go to one of the more specialised running shops for advice on identifying the right shoe type. A decent pair, McKeever reckons, should cost €85-€145.