By Gavin Stamp
BBC News business reporter
January and February are traditionally a time of retrenchment, a period for reining in personal spending and working off the excesses of December.
People are interested in knowledge building at this time of year
As people tone down their conspicuous consumption and focus more on self-renewal, the door is opened to businesses which cater for those looking to learn new skills and improve their lifestyles.
January and February is a make-or-break time for these firms in contrast to most other companies for which it is a quiet time.
Their sales over the period will determine their financial performance for the whole year.
January is a vital time for publishers of partwork magazines, 'hobbyist' publications designed to be collected as a series over several months.
These titles - most of which are published this month - generate annual sales of more than £100m and appeal to a range of different buyers.
These include followers of cult TV programmes such as The Prisoner and Star Trek, those wanting to learn the basics of skills such as aromatherapy, yoga or embroidery and anyone who take delight in assembling a model of a World War II battleship or a new rally car.
"With Christmas over, people are looking to take up new hobbies and thinking how they can fill their time," says Helen Wilkinson, circulation marketing executive at the Periodical Publishers Association.
"It is winter and many people are not doing much outdoors activity. They are looking for something along these lines."
Partwork publishers rely heavily on television advertising to generate interest in their titles and advertising is generally cheap at this time of year.
"They need to hook in customers from the first issue," says Wilkinson.
Those looking for a more vigorous physical challenge are equally sought after by the UK's 2,000 private health and fitness clubs.
When people join gyms
Source: Fitness Industry Association
Industry research shows that people are more likely to join health clubs in January than in any other month.
Studies also suggest that most people stay with a club for at least a year once signed up, making the annual scramble to recruit members every new year even more fierce.
"If January and February were poor we would be worried about the potential for the rest of the year," says Andree Deane, communications director of the Fitness Industry Association (FIA).
Firms are acutely aware of the once-a-year opportunity they are given in January to maximise sales.
Many companies waive joining fees - which can typically cost as much as £200 - in January to entice new subscribers while others are offering valuable incentives to existing subscribers to sign up family members and friends.
David Lloyd Leisure is offering current members a range of free goods including MP3 players if they recommend new members.
"We offer very generous referral schemes because they bring members who will stay," says company spokesman Mark Webb.
"If you are attracted by huge discounts and you are making these outrageous resolutions to lose several stone you may lose heart quickly."
Getting back on track
The increased emphasis on personal health that a new year generally brings is potentially lucrative for specialist retailers selling slimming plans, detox diets, supplements and preventative remedies.
Specialist health retailers get new customers in the winter months
Holland & Barrett is seeking to capitalise on increased interest in many of its products by selling the most popular items - Cod Liver Oil, Vitamin C, Gingko and St John's Wort - at half price throughout January.
"We probably get quite a lot of new customers although our marketing is not aimed at this more than at any other time of the year," says Sharon Morey, the company's director of regulatory affairs.
"There is an upturn in sales for certain product categories. People are thinking that if they have overdone it over Christmas they need something to get them back on the straight and the narrow."
January isn't merely a boom time for companies serving our desire for a more healthy lifestyle and helping us endure various privations.
For haggis producers, January is the busiest month of the year
Burns Night - celebrated in Scotland and around the world on 25 January - marks an early return to the festive spirit of year end.
For haggis producers like McLay Wallace it is the most significant day of the year.
Sales in January account for about 40% of the firm's annual turnover and McLay is currently producing a ton of haggis every day seven days a week.
This year is a particularly hectic one for the firm since, for the first time, it is producing haggis in the United States after setting up a joint venture with a company in Maine.
"There is a burst of activity throughout the January season and it is all hands on deck," says joint managing director Gordon Wallace.
"There are not many people sitting behind desks."