Akademik

Нет правил без исключения
There always exists something that diverges from, or contradicts any established theory, belief behavio(u)r, etc.
Cf: There is an exception to every rule (Am.). There is no general rule without exception (Am., Br.). There's no rule without an exception (Am., Br.)

Русско-английский словарь пословиц и поговорок. . 2013.