You can set it up to advertise on certain days of the week ( Lets say you are on customer sites a couple of days a week and only available to take calls on a Monday or Thursday), you can choose the times.. You can pause it for periods when you are too busy or increase your budget when business is slow. And the best thing of all, is if it's not working for you simply stop using it... unlike the Goldenpages or Independent Directory where you must signup for the year. If you intend to use Adwords, one thing to point out is that you should insert code on your web page or blog which will enable you to analyse and monitor all the visitors to your website in real-time. I'd recommend www.statcounter.com or www.google.com/analytics/ for this. Google Anaytics also links and integrates very well with Google Adwords. Using this you can learn in 'real time' which keywords are the most profitable for you...