For those of you who were not forced (at gunpoint) to take Latin lessons in school, 'caveat emptor' means, simply, buyer beware and it's a salient phrase to use in respect of Adwords. Back in May 2009 I posted about the dangers of setting large budgets in an untuned and untested account and I'll expand on that here.
Adwords is not a simple product to run and use effectively.
This message is, I believe, not pushed home forcefully enough by Google (understandably from a marketing point of view) and it leads the unwary into opening accounts and spending money with little of the learning and knowledge they need to do so efficiently and get worthwhile results. Even 5 or more years ago there were many twists and turns in the Adwords system. Today there are 10 times as many and some very complex and confusing factors can come into play when designing and operating an account. The posts from hapless users continue in the support forum: "I've spent $400 in the last two days and had no calls...", "Adwords says I'm getting 100 clicks a day so why haven't I had any sales?" and so on.
It is not just the sums of money involved here that are disturbing. It is also that many of these posters exhibit such a complete and total lack of understanding of Adwords. It's like finding someone with a car crashed into a lamp post, saying "I don't know what happened, am I supposed to do something with that wheel thing or those little pedals on the floor?".
It's easy to see how a business owner might jump at Adwords as an opportunity to improve sales quickly. But, if the owner intends to run the account themselves, there is no benefit to be had in going too fast, knowing too little. Some time learning and asking questions will reap far greater rewards than trying to knock something together in time for the weekend.
Of course, if the need is time-sensitive then there are always consultants who'll be more than happy to assist and, given the right consultant, this can also be a route to learning over time.