Your kids may see the situation quite differently than you do! But sometimes the way they ask for things are not appropriate or the best way to reasonably ask for them. Try to instill in them a sense of self-ownership and make them earn what it is they want. That can be through letting them control their own set spending limits or coaching them when they are being obstinate, instead of just bowing down and purchasing things for them. Whatever your method if you can make them realize the value of the things they want, they will be better prepared to function in the real working world.