What is the best time to patent our product?

Apart from filing strategy, what will you do with a patent if granted? Do you want it to license to competitors? Can a competitors circumvent it? How easy is it to discover someone using your invention? ( so you could license or exclude them?) do you have the money to litigate to enforce it if granted ? Normally allowance is a good 3 years from filing (less if you qualify and pay for accelerated examination) - will your patent have value in that timeframe (e.g., the company will still exist)? Yo can always sell a provisional application or an issued patent, but well before you start the meter on drafting and filing expense you need to answer those basic ROI questions.