You will lose your right to a patent if you fail to pay maintenance fees to the patent office, which ultimately results in the patent expiring.
For this reason is is very important to keep your patent up to date and always inform the relevant patent office of your current address to receive correspondence and fee information.
The inventor will lose their right to patent an invention of the inventor has disclose the invention in a printed publication more than a year before applying for an a patent. The offending description must be clear and exact so that a person who is skilled in the area of the invention could duplicate it. A vague description of the invention will not adversely affect the inventor’s rights.
If the invention was published within a year then its the inventors responsibility to apply for a patent as soon as they can. it doesn’t matter if the invention was published in the US or anywhere else.
If the inventor offered the product for sale in the US more than one year before the inventor applies for a patent, the inventor will lose patent rights. This one year timescale gives the inventor time to test the market and perfect the features of the product. Its important to note that during the one year the invention needs to be functional rather than experimental.
An inventor can abandon an invention in many ways but the essence of abandonment is that the inventor appears to have given up the intent to patent and let the patent lapse or doesn’t file the initial patent.
In the situation where the inventor chooses not to patent the invention rather conceal it then there is not timeframe to patent. If another inventor applies for a patent on the same invention the initial inventor loses right to patent (only if the second inventor came up with the invention independently and in good faith).
You do not need to patent an invention as soon as you come up with the idea but be warned that delaying a patent on an invention may potentially leave you at risk.