For the first week I change bedding every day to prevent any contamination to the little chicks with poorly developed immune systems. So when we change bedding we pick up each chick to place it in a "holding" box, turn the chick upside down, check butt, feet, wings, anything unusual. So every chick gets handled at least once per day.
And since the brooder is in our home office one of us is almost always in there on a computer or on the phone. So we make it a habit to pick up a chick when we walk in the room, extra socialization and we can check out the chick for any problems.
Once the chicks are two weeks old we have decreased changing bedding to every 3rd day, just add fresh bedding as needed in between. But since the chicks are older and less susceptible to becoming ill (keep hand sanitizer right next to coop at all times from day 1) we hold the chicks while we are sitting around and even invite the older neighbor kids to "come see the chicks!" When we have more than a few chicks it really helps to have extra hands and laps to socialize. I like mine to be friendly, the type that follow us around in the yard and are easy to approach / pick up.
