In almost all circumstances, an entrepreneur or startup company should NOT get a provisional patent application. The main purpose of the provisional application is to *delay* the patent process. A delay is very useful for circumstances, such as pharmaceuticals, where most of the value of the patent is at the end of the patent term. This is not the case for almost all startup companies.
First, having a patent application quickly will add value to the company. It makes business sense to get patents as fast as possible, since the company’s valuation will go up if you are raising money, and it gives the startup company at least some protection in the marketplace. I suggest using the Patent Prosecution Highway or Track One to expedite the patent to try to get a patent within 1-2 years, not the sometimes 5-7 years without expediting.
Second, a “thin” provisional application does far more damage than it helps. Many people file a 1-2 page provisional application, then think they will come back a year later and pay an attorney to write a “full” patent application. Entrepreneurs often think that they are “protected”, so they go out and freely discuss their inventions with customers, investors, and the general public during the one-year period.
This creates a situation where you have two filing dates: a first one for the provisional and a second filing date with the rest of the material.
The “full” patent application probably has much more material that is needed to support the claims in the patent. This creates a weird problem: the provisional application is “prior art” against you on later patent applications, but it is not enough to support the claims. The damaging prior art will hurt all of your future patent applications.
All European and other international patent rights are lost through this process. The European Patent Office requires full support for claims in the specification. Since you didn’t have this support in the provisional, then you talked about the invention publically before filing the non-provisional, your international rights are lost.
If the invention is truly valuable, it makes much more sense to pay for a competent attorney/agent to draft a full, complete patent application covering every variation you can imagine for your invention. File this application as soon as possible, and grow your business accordingly. There is nothing more depressing than to tell an entrepreneur that much of their patent rights were lost because they tried to save a couple dollars by filing a provisional.