Yes, wood naturally changes color. It will turn to a weathered gray color within a year. You could power wash the surface once a year to help retain the original color and beauty. However it is strongly recommended to stain or paint the deck for increased longevity.

It is not unusual for wood to splinter but different types of wood have different grain patterns and densities, which make them more prone to splintering, splitting or cracking. There is no warranty/guarantee on wood.

Every 2 years but it really depends on the amount of shade and moisture around your woodwork. It also depends on your preference.