Watsons Your Personal Store has come a long way from dispensing anti-worm tablets. It is now a dynamic global player with more than 1,500 outlets in 13 countries - not counting a similar number of outlets in a fast-growing portfolio of retail chains acquired by the AS Watson parent group across Europe.

Over the past decade the Personal Store brand has extended its tentacles way beyond Hong Kong, where there are now about 170 stores and 52 pharmacies.

Across Asia, the chain is in the mainland, Macau, Taiwan, Singapore, Malaysia, Thailand, Indonesia, South Korea and the Philippines. More recently it has pushed into Europe, exploring the markets of Turkey, Estonia and Slovenia.

The logistics of merchandising more than 20,000 products - or stock-keeping units - ranging from medicines, cosmetics and toiletries to fashion items, confectionery, cards and toys for this diverse network is complex.

As the name of the retail brand underlines, the health and beauty business is 'personal'.

Products and packaging not only change with modern trends, but also according to local needs and tastes from season to season, country to country, and at a micro-level even from one district of a city to another.

The key was careful monitoring of each particular nuance, said Simon Mak Chi-sing, the chain's merchandising director for Hong Kong and Macau.

Speciality products go on the shelves for Christmas, Lunar New Year and Easter, for 'back to school' seasons and for the Mid-Autumn Festival, when mooncakes are in demand.

'During summer we stock up on suntan lotion. Diarrhoea products are also in more demand in the summer holidays,' Mr Mak said.

Vitamin C along with lip balm and moisturisers are big movers during the winter influenza season.

'The weather plays an important part in merchandising, especially in Hong Kong,' he said.

'We don't do a lot of chocolate in summer, but we do in winter.'

From district to district, 'personal care products are stronger in residential areas, while beauty products are more attractive to office ladies in the city'.

Health products are popular in both - not least due to an 'increased consciousness of Hong Kong people towards health' in the wake of Sars and bird flu.

'Customers are paying much more attention to their health,' said Mr Mak.

'Hong Kong's declining air quality is also forcing much more attention on protection against viruses and diseases. We have also introduced more air cleansing products.'

In a developed market where status and image counts, he also noted: 'Hong Kong customers are exposed to exciting new trends all the time, so there is much more of a challenge keeping up to date with trendy products.

'These trends also change all the time, so we need to react to customer needs rapidly.'

Mainland consumers differ further. With much less disposable income, they are more practical in their tastes and preferences, looking for value for money rather than high-end beauty products. As in the Philippines, Vietnam and Thailand, they also buy a lot more small products.

'Every country has its own culture and customer preferences,' he said.

With increased concern about global warming, there is a trend towards 'green' and organic goods, from environmentally friendly bags to organic skin-care products and snacks.

Keeping their fingers on the pulse of these market trends is a buying team of more than 40 just for the Hong Kong and Macau outlets.

'We source products from all over the world,' said Mr Mak. Both local and international trade fairs are good hunting grounds, since many manufacturers showcase new products in one venue.

'We can go to a trade fair in Germany to buy chocolate for Christmas and be sure that our customers cannot find the same product anywhere else in Hong Kong,' he explained.

The media, especially the internet, is also an increasingly important source of information on new trends and products. As the chain becomes increasingly well known as a global force, manufacturers offer products directly.

The Personal Store buying team is also supported by a separate ASWatson division called International Buying, which sources for all the group's Asian retailing chains, including ParknShop supermarkets, Fortress electrical goods stores and a range of smaller formats taking in Watson's Wine Cellar, TASTE food Galleria, Great Food Hall and Nuance-Watson duty-free shops, as well as European chain acquisitions such as Superdrug, Savers, Kruidvad and Trekpleister.

The global expertise and buying power at AS Watsons clearly gives the chain a competitive advantage, with greater size translating into larger buying power. By buying in bulk and bringing its bargaining power to bear on suppliers, the company can source products at lower costs, which can then be passed on to consumers in the form of lower prices.

'A huge volume of buying always mean lower prices, which is the main reason we can deliver good quality products to customers at lower prices,' Mr Mak said.