"une dizaine de fois" vs "une douzaine de fois": Which phrasing comes more naturally to French speakers?

Question

J'ai déjà dû répéter tout ça une dizaine de fois.

J'ai déjà dû répéter tout ça une douzaine de fois.

Here, I'm not talking about the exact number of times I've done something, but rather I want to emphasise a moderately large number.

I wonder which of these two numbers French speakers use more commonly: ten or a dozen?

The same goes for:

Si seulement j'avais eu ne serait-ce qu’une dizaine/douzaine de personnes coopératives autour de moi !

Answer 1

We still use douzaines for eggs, oysters, snails and a few other delicacies but for "a moderate number of times", while une douzaine is certainly idiomatic too, my impression is une dizaine prevails.

Google Ngram shows the metric system in action:

Answer 2

I understand you are looking for colloquialisms. In this instance, "douzaine" is better if you want to express, let's say, annoyance. But what would come naturally to me is "une demi-douzaine" - j'ai dû lui répéter ça une demi-douzaine de fois numerically inferior but rhythmically superior sentencewise, if you see what I mean.