In chapter 5 of Mastering Bitcoin, Andreas writes:
"The disadvantage of random keys is that if you generate many of them you must keep copies of all of them, meaning that the wallet must be backed up frequently. Each key must be backed up, or the funds it controls are irrevocably lost if the wallet becomes inaccessible. This conflicts directly with the principle of avoiding address reuse, by using each bitcoin address for only one transaction."
If we are using each bitcoin address for only one transaction, how does this result in address reuse?