  In this paper we give an elementary approach to several results of Chatterjee
in arXiv:0907.3381 and arXiv:1404.7178, as well as some generalizations. First,
we prove quenched disorder chaos for the bond overlap in the Edwards-Anderson
type models with Gaussian disorder. The proof extends to systems at different
temperatures and covers a number of other models, such as the mixed $p$-spin
model, Sherrington-Kirkpatrick model with multi-dimensional spins and diluted
$p$-spin model. Next, we adapt the same idea to prove quenched self-averaging
of the bond magnetization for one system and use it to show quenched
self-averaging of the site overlap for random field models with positively
correlated spins. Finally, we show self-averaging for certain modifications of
the random field itself.
