Youth sticks are the appropriate size for players aged 4-8. Intermediate sticks accommodate ages 10-15 and senior sticks fit players ages 14 to adult.
The most important thing that you need to know when picking out a hockey stick is how much flex the stick has. Often when first getting into hockey, you'll want a high amount of flex in your stick so that you can easily get shots on net, but as you grow as a hockey player, start off with about half of your body weight, and then eventually find one that fits perfect for you.
Junior sticks typically feature a flex 50–52. Intermediate ranges between 65–67, and youth hockey sticks are generally available in a 40 flex. All manufacturers offer their flex ratings as standard across all models.
If you have your child try on a hockey stick, make sure that it is resting at the tip of their nose. When placed this way, the stick should be secure, but also comfortable for them to hold in their hands.
Youth hockey sticks are typically 20 to 30 flex and typically for ages 4 - 8 (weight 40 to 60 lbs) whereas junior hockey sticks are generally 30 to 50 flex and built for ages 7 - 13 (weight 60 - 100 lbs). A 10 year old should use an intermediate stick with flex somewhere between 40 and 50 depending on their size.