WHY A PATENT SEARCH CAN HURT YOU!
In the first place, you should NEVER hire someone to make a search for you! If I can go through 100 patents in an hour and you buy one hour of my time, if the best reference is Number 110, we will never see it! Also, you cannot afford to buy a search where I can guarantee that I have seen the best art, since this could take days or weeks of time and would cost tens of thousands of dollars - which is not the real world!
However, if I can't guarantee you that I have found the best references, what have you bought? You've bought a pig-in-a-poke! There may be many references out there which are as good as or better than what I found, but you'll never know it. Therefore, if you must make a search, make it yourself! In most major cities, the Patent Office has set up their computerized search system at a main library and have trained the library staff to use it and to train you to use it - for free or for a very nominal fee. So the search you can make will be at least as good as one you can buy. Furthermore, you will see all of the references, so you can decide which are pertinent and which are not, instead of relying upon someone you hire to make that decision.
THE TIME TO MAKE A SEARCH
The time to make a search is before you make an invention - NOT afterward! But, you ask, how can you make a search before you make an invention? Actually, you can. The way that most major companies start a project is to decide what area of technology they wish to invent in. Now, the U.S. Patent Office has all technology broken down into classes and subclasses. So, you get a copy of the Patent Office Classification Manual and find out which classes and subclasses relate to your field of interest. Then, you can find out what patents are in those classes and subclasses. Now you start and go through these patents - patent by patent - looking at every patent which has issued over the last 5, 10 or 20 years. This puts you in the position of a "Monday-Morning quarterback" - you can see everything that has been done in that field over whatever length of time you look - and, as you do, you will find one patent and say "That's a stupid idea! I don't know why anyone would want to do that." However, you may also find one where you say "Now, that's not a bad idea - but they didn't have it quite right. What they should have done is ....". YOU'VE MADE AN INVENTION! It's that simple.
HOW A SEARCH CAN HURT YOU!
Now, I said that you should make a search BEFORE you make an invention. After, you have an idea, DO NOT make a search! Why? Because, once you have an idea, what you want to do is to take it from concept to cash. Filing a patent application will protect you while you do this. Making a search does nothing to protect you and may actually hurt you! Filing a patent application (Either a Provisional or a Utility application) allows you to mark your device "Patent Pending", which will tend to scare off competitors while you get your product off the ground and establish a market position.
Furthermore, once you file a utility application, we can keep it pending for ABOUT FIVE YEARS! - REGARDLESS OF WHAT REFERENCES ARE OUT THERE! If you filed a Provisional Patent Application, you have that year also, making a total of SIX years and there are ways that you may be able to keep your utility application pending longer that that. During this time, you can continue to mark your device "Patent Pending". HOWEVER, when you file a utility application, you have to sign an oath, which states that you believe that you are the "original and first" inventor. No problem. You've come up with an idea and don't think anyone has anything like it. Also, you've talked to several friends and they haven't heard of anything like it. So, you sign the oath, file the application and you have at least two years to mark your device "Patent Pending" BUT suppose you make a search and find a reference which is very similar to your device. Now, maybe you are not so sure that you are the first inventor. Now, if you sign that oath, it would be perjury. You could be sent to jail! Now, you can't file the application and you can't mark your device "Patent Pending". So, you've shot yourself in the foot. But, you are not required to make a search. So I say, "You don't want to know, so DON'T LOOK!