So don't target "widget" when you sell "super rare special widget"
Because you would get 10000 impressions for "widget" and only one guy actually looking for "super rare special widget" and your CTR would be to low.
just bid on the specific keywords so you maintain your CTR of 1%. Won'T worry about having only 100 impressions and 1 click in a month. try to cover all the possible obscure and long keyword phrases that apply to your niche product, and you should be covered.
SN
Don't worry and let it fly. Easy to change keywords at whim. Costs are real easy to cover for a nich products.
The one problem that I am havng though is that it is too easy to play with. I've looked at the control panel at least 3 times today. :)
It is not the number of clicks that matters at all. What *is* important is the Clickthrough Rate (CTR), which is the ratio of clicks to impressions.
(The boring details: CTR is your clicks divided by your impressions, expressed as a percentage. Thus 1 clicks divided by 100 impressions = 1% CTR).
For example, 25 impressions in a week, and only one click, gives you a golden 4% CTR. And the targeted keywords that Killroy suggested are key to getting this kind of results.