Advertising is an investment, and, especially as a startup with limited resources, you need to get a quick return on your investment. That is, you better be getting customers from your advertising spend, or you’ll run your company into the ground before you can say “IPO.” You don’t have the resources to waste money on advertising that isn’t working.
While it isn’t always black and white, an easy metric to help you determine whether your advertising is working is whether you are able to turn $1 into $2. Does every $1 you spend come back to the company as $2 in sales? If not, move on to the next advertising channel and keep experimenting. Repetition is the key, of course, so don’t bail immediately if you don’t see results. However, you should be able to ascertain relatively quickly if a channel is working or not. If not, don’t linger for too long. There are hundreds of ways to reach customers these days, so try another channel.
Also, don’t settle for turning $1 into $1. As tempting as any revenue may be, $1 isn’t enough to build your business. You need profitable revenue to fuel growth.