I came across these translated examples:
[Talking about a place]:
Mínɡnián xiàtiān wǒ dǎsuàn qù yí cì。
I plan to go there next summer.
Sān nián yǐqián wǒ qùguò shànghǎi, qùnián wǒ yòu qùle yīcì, míngnián wǒ xiǎng zài qù yīcì.
I went to Shanghai three years ago, I went there again last year, and I want to go again next year.
In English (or Spanish), typically we would not say "you go one time to a place", one time is already implied in the verb to go and it feels weird to state it unless you want to emphasize for some reason "you are going just one time". Why 一次 is specified in these examples? Previously, I had understood the use of 一次 in the second example was required for 又 and 再, however the first example does not have any special structure.