When your kids first started taking their piano lessons they were probably excited and very willing to practice every day. Now you might be frustrated that the piano isn't even touched very often. If you want your kids to be serious about playing the piano, here are some ideas that might help.
Have A Heart-to-Heart Talk With Your Children - Sit down with your children individually and talk to them about their piano playing. Do they already know how much you are paying for piano lessons? Until they can see that piano lessons are a sacrifice for you, they may not realize how important their playing the piano is to you. The thing is, maybe playing the piano isn't really important to one or more of your children. Ask them not to give you answers that they feel you want to hear. Instead, ask them to be frank with you. Do they want to play the piano, or not? If they don't, spare yourself some grief and save yourself some money by letting them bow out. Perhaps later they'll have more interest.
If the response is that playing the piano is something your child wants to do, set some rules. Talk to the music teacher and get guidelines for how long your child should be practicing each day. Perhaps you can be flexible and tell them that they can miss one or two days or practicing, but stick to you guns on consistent practicing the other days of the week.
Have A Heart-To-Heart Talk With The Piano Teacher - If any of your children has decided to quit, it will probably be easier for you to inform the teacher. For those who have decided to stick with piano playing, ask the teacher if he or she can help your children set actual goals. It may be that, instead of assessing a certain amount of practice time, the teacher may ask that the child memorize a piece by the next practice. Ask the teacher to include some of the child's favorite songs. For example, very young students may love to learn pieces from children's movies. Old children would probably be thrilled to learn pieces from movies like Star Wars or The Hunger Games.
Ask your older children to monitor their own practices and to account to you for the time they've practiced. For little children, it will be helpful for you to sit close to them while they play.