QUESTION: Can filing a provisional patent application hurt?
Beyond the filing fee and time spent drafting a provisional patent app, are there any reasons not to file a provisional app? More accurately, could filing a poorly drafted provisional be worse off that not filing one at all? If it’s later determined that the provisional was inadequate, a non-provisional can still be filed that doesn’t claim benefit from the provisional, so long as the non-provisional was filed within 1 year of public disclosure, right? Also, a hypothetical situation: Let’s say I filed a provisional containing subject material A, then immediately went public with the invention; 6 months later, during product testing I discover new material for the invention, let’s call it B. If I file a provisional containing A+B (as soon as B is discovered), when is the non-provisional claiming A+B due? 1 year from provisional A or 1 year from provisional A+B?

ANSWER: Generally, filing a provisional is better than not filing anything – even if the provisional lacks information. In the above example, you could file a non-provisional within one year of filing provisional A, in additional to within one year of provisional A+B.