It takes planning.
Advertising works best and costs least when planned and prepared in advance.
For example, you'll pay less per ad in newspapers and magazines by agreeing to run several ads over time rather than deciding issue by issue. Likewise, you can achieve certain economies by preparing a number of ads at once. The effectiveness of your advertising is measured over the long run. That's because people don't see every one of your ads. They only see some of them some of the time.