We never pushed time with DS6. He knew how to read a digital clock at age 4. He's now learning the regular clock in 1st along with his other classmates. But I will say, they just started maybe 2 weeks ago, and he's grasped the concept so extremely quickly and is leaps and bounds ahead of what he is supposed to know (they are only teaching :00 & :30, DS can tell you pretty much down to the minute, i.e., 4:17).