I have some questions concerning credits.
First of all, is there a preferred/recommended way to write them? Beginning/end, duration, etc.?
Sometimes I forget to write them. what then?
What if I get somebody else's work and make some changes? Could I remove the original author if they are very big?
Well, I'll give my opinion.
It does not matter much that is at the beginning or end, as long the credits are in the subtitle..
There are translators who only write the credits at the end.
There are others that write in the beginning and at the end.
Duration, It depends on each translator.
For example in the translations that i do, the duration of the line of the credits It is 5 seconds.
No matter that many are the changes you have made in the subtitle.
I think the original credits should always be kept.
Keep the original credits and add your credits.