Give a tl;dr for the following Reddit post - 

Questions for Parents ...

When it comes to buying books for kids, when do you decide to buy a books vs borrowing from the library?

I want my son (currently age 4) to have a collection of books but I'm trying to keep my spending under control .

I'm also finding that he is usually excited to get new books vs the ones he owns. (But this is slowly changing as I purchase his favourite ... vs the random books we've been gifted)

Right now I'm trying to follow these these rules...

Buying some of super popular books that constantly have long hold (usually in our family's favourite franchises)

Buying books my kid never wants to return

Buying books the library doesn't have and I really want him to have read

How do you manage book buying for your kids?

Do you only buy books for birthday/Christmas or buy books regularly as they move into different interests/reading levels?

Do you know how many books you own for your kids current age? (We own 20ish books that are age appropriate)
I have a four-year-old son and currently buy books the library doesn't have, popular books, and books he doesn't want to return. When do you buy books for your kids instead of using libraries? 