Whether the same parts are omitted when noun phrases are juxtaposed？

I’m writing about an essay about general upper secondary education and vocational upper secondary education.

But when I have to put them together, I’m just confused, whether writing ‘general upper secondary education and vocational upper secondary education’ or ‘general and vocational upper secondary education’.

Under what circumstances can people omit the same parts and under what circumstances can they not? Could you tell me the rules, please.