In general, I suggest parents steer clear of using rewards in everyday parenting. The main reason is rewards tend to introduce extrinsic motivation for behavior which decreases intrinsic motivation. In other words, you decrease the behavior you were trying to increase. Rewards tend to work against you.
If you find yourself setting up a reward or starting to bribe a child for behavior, you are on better ground offering the child a positive logical consequence. Positive logical consequences are things related to the behavior itself. Rewards tend to be unrelated.
Let’s say I am a second grade teacher, and I say to my children, “for every book you read this week, you get a sticker. The class with the most stickers gets pizza on Friday.” I am directly decreasing the interest in reading. I am increasing the interest in stickers and pizza. Books are now the obstacle in the way of stickers and pizza. I will read the shortest fastest books I can, I might even lie about the books I read because I want stickers and pizza. If I am in the class that realizes on Wednesday we aren’t getting pizza, we are done reading.
To keep intrinsic motivation for reading the idea is to offer positive logical consequences or things related to reading. This might be, “for every book you read, you can check out an extra book. The class with the most books gets double library time on Friday, or gets to watch the movie that goes with the book on Friday.” Positive logical consequences stay on topic with the behavior, reading for reading builds intrinsic motivation for reading.
If you start to pay your child to practice piano, you are directly decreasing their interest in piano playing and increasing their interest in money. To keep intrinsic motivation for piano, you might offer that for every week they practice piano, you will sit for a recital, or they can download more sheet music.