Many countries bar patenting of a concept if there is any public disclosure (and sometimes any attempt at commercialization) of that concept before the filing of a patent application.

The US allows a one year grace period from the non-confidential disclosure, offer for sale, or commercialization of a concept until a US utility patent application describing that concept must be filed if a US utility patent is desired.

Consequently, if there is a desire to preserve the right to file a patent application outside the US, a US patent application should be filed before any non-confidential disclosure, offer for sale, or commercialization of a concept occurs.

Once an initial patent application is filed in most countries (including the US), any desired foreign or international patent applications must be filed within no more than 1 year (but immediately in a few countries). 

If a US provisional was filed and a US non-provisional is desired, it must be filed within 12 months of the filing date of the provisional.

Despite these time limits, to protect rights in a valuable inventive concept, it is often worthwhile to file some form of patent application as soon as possible.  Doing so will provide a filing date that defines what “prior art” can be used against the claims of any non-provisional patent application filed (now or later).  Because one never knows when uncomfortably close prior art might emerge, time might be of the essence.