The most common and most likely answer to this crossword clue is the 5 plus 4 plus 5 plus 2 plus 7 plus 3 letter word THERE WILL NEVER BE ANOTHER YOU
I've seen this crossword clue in The Guardian
T
H
E
R
E
W
I
L
L
N
E
V
E
R
B
E
A
N
O
T
H
E
R
Y
O
U
Buddy explains!
The straight part
We know that "Standard" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case standard = there will never be another you.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.