It depends on many factors. Remember that it takes three to seven times for someone to remember your name and seven to 15 times before the typical consumer will take action.
One of the questions you need to consider is whether you are a new business just starting out. If so, then you might want to send out a news release to your local newspapers and radio and television stations announcing the opening of your business. This is free advertising. You might want to place an ad in a local newspaper or on a radio station.
Once you have established a customer base, the best form of advertising is word of mouth. Just remember, initially, the community won't know you exist. So, putting money into advertising could be a good investment.
Ideally, you want to encourage repeat customers. The advertising may attract a customer to your product the first time, but it is the quality of your product and your customer service that will bring them back again.
Anytime you make a change in your business such as adding a new product, changing your location, or adjusting your hours, you may want to do additional advertising. Many businesses adjust their advertising seasonally to take advantage of their customers' buying habits.
No matter what type of advertising you use, it is really important to evaluate how well it works for you. If advertising does not translate into sales, then you may not be using your time and your money wisely.