You have a book and you grew out of it. Just like clothes, it happens. But, should I just throw it away?
If you have books that you no longer need, give it a new home rather than tossing it in the garbage or recycling bin. Donate them to community centres, schools, or local libraries. You can even consider starting a local mini library at a central spot in town. I’ve seen communities install a box where people can drop off books and borrow books at their leisure. There’s so much knowledge packed into a book. Although you’ve finished gaining from it, that book still has a lot to give to others even if it’s a bit old.