Long journeys start to ruin every kid's summer (5)

I believe the answer is:

treks

'long journeys' is the definition.
(I've seen this in another clue)

'start to ruin every kid's summer' is the wordplay.
'start' indicates taking the first letters.
The first letters of 'to ruin every kids summer' is 'TREKS'.

(Another definition for treks that I've seen is " migrations".)

I've seen this clue in The Irish Times.

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