Fill in the gaps with "would" or "used to". Sometimes both options are possible. In this case, use any of them.
My father say: "The first one to get angry loses."
We use would as an analogue of used to, when we speak about some regular actions and habits in the past.
When I was younger, I would drink five cups of coffee a day. (= I used to drink...)
Do you remember? When we were kids, we would run through the field, climb the hill and hide under the big oak tree. (= we used to run...)
In the examples above, we can either say "would" or "used to". But we can't use "would" when we talk about states in the past and not physical actions.
When Fred was a student, he used to have a beard. we can't say ... would have a beard, because it isn't a regular action
When we were children, we used to live in the countryside. we can't say ... would live, because it isn't a regular action