The most common and most likely answer to this crossword clue is the 7 letter word SCHTICK
I've seen this crossword clue in The Guardian
S
C
H
T
I
C
K
Buddy explains!

The straight part
We know that "Familiar routine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case familiar routine = schtick.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SCHTICK mean?
SCHTICK noun- A generally humorous routine
- A characteristic trait or theme, especially in the way people or media present themselves.
- A gimmick.