A teacher of English or another language can read books and web sites (like British Council - BBC) to improve technically his ways to teach and help students learn the language.
The teacher can recycle his training by those means.
Maybe he will re-discover a technique or a method.
And non-native teachers of English can keep on learning and practicing English: it is a life-long learning. / Photo from: two-business-people-talking-face-to-face shutterstock com