It does depend on the child.. In daycare they will have a quiet time.. they can sleep or they can lay quietly. Usually 1 hour to hour and a half.
Toddlers do not want to feel like they are missing out on anything.. If it is daylight in their rooms and they can hear the TV and cell phones going, people talking outside, they think there is a party they are missing out on..
They need a naptime routine just like night time.. have a quiet lunch, wash up with warm water on their hands and faces, quiet voices, story maybe with a back rub.. then nap time.. or at least just laying in their rooms listening to a book on CD.. EVERY day even the weekends.. Kids love schedules..
Also children need ACTIVE play .. Once in the morning and again in the afternoon.. again for an hour or an hour and a half.. There is just so much energy in those little bodies that they need to use up..
If all they do in the morning is play quietly, sit in a grocery cart and then come home for lunch.. they have not had a chance to get rid of any of that energy.. Of course where we live kids can go outside almost every day, so it is probably easier for us to "run our kids" than it will if you all are inside because of weather.. Maybe put on music and dance, maybe do some Simon says, hopping, jumping, etc.. Have them ride heir trikes outside..