An easy question: can you tell me why many manufacturers say that the packaging should be opened only when installation is ready to begin (but do not explain why)?
What could happen if i open the boxes one week before to inspect it ?
I thought it was easier to let it adjust to temperature and humidity conditions of the installation site if the boxes are open!!!

The packing keeps it tight. The plastic on the cartons is not air tight, unless you bought a Kahrs floor.

Once you open some flooring cartons, within the hour, you can see some boards start to bow, and banana.

Always follow manufacturers recommendations. There are reasons for it. Perry mentions one point. Another is that some products are milled so tight(especially floating floors) any introduction of moisture will create an installation problem with the fit. Boards will expand.

Thanks Perry and Ken, yes, i follow recommendations but i like to understand the reason. i wonder how people buying online can wait until the installation before inspecting what they have bought