The most common and most likely answer to this crossword clue is the 7 letter word FORTIES
I've seen this crossword clue in The Guardian
F
O
R
T
I
E
S
More clues leading to the result FORTIES
Buddy explains!
The straight part
We know that "Time of life" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case time of life = forties.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 FORTIES mean?
FORTIES noun- The decade of the 1840s, 1940s, etc.
- The decade of one's life from age 40 through age 49.
- (temperature, rates) The range between 40 and 49.
- From or evoking the 41st through 50th years of a century (chiefly the 1940s).
- A bottle of beer containing forty fluid ounces.