I don't know where you heard that 10 day thing. It just ain't so! You can store them a week in reasonable conditions (avoid extreme temperatures and try to avoid extremely low humidity, but humidity is harder to control) If you store them over a week you need to turn them a few times a day. With reasonable care they are good for about 2 weeks. After that the hatch rate starts to drop fairly fast though you can still get several to hatch. You need to collect all the eggs you want to hatch and start them at the same time so you will not have a staggered hatch, but an egg that is freshly laid is ready to incubate.
That rule usually only applies to shipped eggs. Eggs that have been shaken, bumped, jarred and God only knows what else USPS does to them will need to have the contents settle prior to incubation. As for an egg freshly laid and gently walked from the coop to the house need not have to settle for 12-24 hours.
I keep mine stored and rotating for up to two weeks just because I want that many eggs to incubate at once. If I had enough hens to lay (and all the same breed I wanted) amount of eggs I want to set in one day then I'd start them incubating that same day.
