Children's clothes are washed more than any others in the house. A few habits make them last long enough to hand down.
Forty is plenty
Modern detergents work at 40°C, and 30°C is enough for clothes that are worn rather than dirty. Hot washes fade colour and tire elastic.
Inside out
Turn prints and dark colours inside out. The outside of the fabric rubs against less, and prints stay crisp.
Line drying is free, gentle and makes cotton smell of outdoors.
Skip the softener
Fabric softener coats cotton fibres and makes them less absorbent. For baby clothes especially, leave it out.
Stains
Rinse with cold water as soon as you can, then rub in a little washing-up liquid before the wash. Sunshine does the rest for most food stains.