As your little baby grows up, she will come to find her once beloved toys a bit of a bore. Babywise mentions rotating toys and keeping them age appropriate, but many moms still find themselves handing their 9 month old toys she played with as a 4 month old and wondering why she seems so discontented.
It does seem to happen around 9 months old. They want new toys. They are more mature and ready for a change. My kids have both lucked out and had Christmas shortly before 9 months hit, so they had lots of new toys. If you have a spring baby, your child will likely have the same experience. Otherwise, very few parents are going to think about getting a bunch of new toys.
It doesn't have to be a lot. You know how you get a couple of new shirts and/or pants and suddenly your wardrobe has a whole new life to it? Get your child a couple of new toys and spruce up the toy collection.
You can also add a lot of ordinary house objects at this age. Measuring spoons or cups, your mixing bowls. A pot with a spoon. Your old cell phone. Look around. Your child is fascinated with new items. Kaitlyn spent about 45 minutes straight one day playing with my measuring tape. I was surprised at her fascination.
Also, be sure to rotate books. If you don't own a lot, take advantage of your local library. Kids get attached to books, but they are also very excited for new books. Just keep it fresh. Keep in mind that your little baby is growing so quickly and needs appropriate stimulation.