How long a buyer should stay in one role is akin to querying the length of a piece of string.

On one side, there's an argument for bringing fresh approaches to new arenas and having a short-term commercial impact, while on the other, there's a case for experience and expert knowledge.

Among buyers, opinions differ on the time a buyer needs to get a handle on a category. Some forum participants plumped for less than six months, while others felt five years was the necessary tenure.

“It usually takes at least nine months before a buyer's decisions start to take effect. Managing range changes, promotions and strategic direction takes this long to filter through to the business,” says one, while another requires more time to fulfil bigger ambitions: “Three to four years would give me the chance to set up and deliver a stunning piece of change that would shake up the market and benefit me and the business.”

The churn for buyers is faster today than ever. “It seems to be even less than two years nowadays, particularly where the big retailers are concerned,” says Rob Seery, manager consultant at recruitment consultancy Nigel Wright. “And the trend is accelerating.”

He puts this down to changes in the retail environment causing movement between retailers, as well as increased commercial pressure from Tesco's rapid growth and the knock-on effect on competitors, resutling in more short-term thinking.

“A new buyer for a price-focused retailer is looking to make an immediate impact that will cascade down to the profit line very quickly,” he explains.

“Other retailers have traditionally taken a more long-term approach. I doubt any senior manager would admit that buyers have been moved to sharpen the commercial edge, though.”

Of course, the time any one buyer stays put varies between categories. Food generalists tend to move more rapidly than those in specialist areas such as fresh produce, wine and meat.

“Clothing and white goods buyers tend to stay put for longer too, although there is an increasing trend among the bigger retailers to move more aggressive food buyers into non-food areas and the short-term approach can really drive profits,” says Seery.

He adds that there are definite benefits for the buyer who settles in for a decent stint: “From my experience, buyers who have been in role for longer than average say that job satisfaction increases as they understand more about their market.”

However, he also points out that this depends on the individual. “Those who really enjoy trading are going to get their satisfaction from that side of things.”

He has some advice for buyers who take too short-term an approach “They must realise that if they offend a big supplier, they will probably have to work with them again at some point,” he warns.

“The supplier won't say it to their face, but they are much more likely to favour rival buyers if there are any stock problems.”

One buyer with many years' experience across different categories, extols the virtues of building slowly. “Sometimes people go in and make an instant impact, then eight months later, they need to redress things,” he says.

“The best way is to build slowly and not expect miracles. A firm foundation is key and then build block by block. You will end up with a stronger structure in the long term.”