Yearlong

6 clues
Lasting 12 months
Lasting for 52 weeks
Like some sabbaticals
Lasting all four seasons
Lasting 365 (or 366) days
Like many magazine subscriptions
Similar answers:
Agelong
Agsalong
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Allalongtheline
Alldaylong
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Allyear
Allyearround
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Along
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Alonger
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Alonglittledogie