Sentence examples for this only once was from inspiring English sources

The 'Allo 'Allo catchphrase "Listen very carefully, I shall say this only once" was spoken not by Louise of the Communist Resistance, but by Michelle of the De Gaulle Resistance.

However, if you do this only once, it's not enough.

Of course, you find out about this only once you're in the kitchen.

Do this only once your dog is calm in the same room as a vacuum cleaner that is on.

I did this only once, for Elizabeth Bishop's The Fish.

Since this AE was only observed once, was mild in severity, and reversible without treatment, its clinical effect was considered minor.

Only once this was in place could success be hoped for.

So, going by this, "you only live once" is all the justification you need for experimentation or extreme effort that might otherwise seem questionable.

This happened only once, I'm afraid.

This is often noticed only once punctuation is absent, e.g. in the case of transcription.

The molecular mechanism of this 'once and only once' control is not understood, and recent results show that centrosomes can also be assembled by a de novo pathway that bypasses this control.