In many situations, if a licensee or funding source is not found during that year, the application is allowed to expire with no regular application ever being filed. In this way, the applicant has a relatively lowcost way to find out if there is outside financial interest in the invention before having to incur all the costs of patent prosecution. Because a provisional patent application does not have to have any particular form, some of the costs in drafting the application can be avoided. There is no need in a provisional application to have a Background section of the application describing the prior art. Also, the provisional application does not have to have any claims, so legal fees associated with drafting claims can be avoided.
Some patent attorneys suggest, however, that the provisional application contain at least one claim.
One reason for this is because the decision to file a continuation regular application is often made at the last moment, very close to the one year anniversary of the provisional application filing date. There is always the possibility that the applicant may neglect to add claims for the regular application. If the regular application is filed without any claims, it will not be entitled to a filing date. On the other hand, if the provisional application contains at least one claim, even if it is not a very good claim, the regular application will be entitled to its filing date. A set of new claims may always be added at some time in the future before the application is examined.