Impact of day care centre on the child's development depends on 2 aspects-
a) quality of environment and care in the centre and
b) quality of interaction with parents.
If the day-care centre is caring and hygienic and you as parents are giving adequate time, love and attention to the child, there should be no need to worry.
2. Thumb-sucking becomes a source of concern when the child reaches the age of getting permanent teeth. It is better to gradually divert his attention when you find him sucking his thumb. But do not make him too conscious of it as he would then do it behind your back.
3. A child who is between 2-3 years old is usually very active and parents may mistake normal activity levels for hyperactivity. It is best to let the problem be diagnosed by a child psychologist and then take remedial steps as advised.