Why you need a website

To maximise the number of your potential customers
To maximise the number of your potential customers who will actually contact you
To maximise the number of your potential customers who can afford to pay for your products or services.

Internet use in New Zealand

A recent study (The Internet in New Zealand) under taken by Auckland's AUT University, found:

80% of New Zealanders use the internet.
71% of internet users rate the internet as an important or very important source of information. This well out rates TV, radio, and news papers.
Over 80% of New Zealand internet users regularly research product information on line to find the local businesses that provide the services or sell the products they want. (By the way 80% of users translates to 64% of the population).
Only 60% of New Zealand internet users purchase on-line, and then only occasionally. They much prefer to make purchases face to face (the exceptions being travel and Trademe).
There is a strong and steady increase of internet usage with rising household income.
The importance of the internet by income becomes most evident for those earning $40,000 per year or more.

Your website provides you with a potential customer base of 64% of New Zealanders.
Realistically, this translates to a customer base of at least 64% of the population in your wider locality.(e.g. Wellington region as opposed to just Lower Hutt).
Conversely, if you don't have a website you are probably missing out to your competitors.
You don't need to have on line shopping facilities.
You do need to give as much information about your services and goods as is possible so that people will want to contact you. You won't be able to do that by traditional advertising.
If you don't have a website your customer base is likely to be skewed towards those on lower incomes.
Your competitors with websites will have a customer base skewed towards those on higher incomes.