when auto increment should used for a column

Question

auto increment gives some trouble when ui does not guess about next ai

Answer 1

Auto increment should be used to increment IDs. As you usually don't select by ID, it's not disturbing if you have holes in your IDs because you deleted a row.
When you insert stuff, you shouldn't choose a precise ID because as they are primary keys, they should always be different. Instead, you should choose default value and say it is an auto increment when you create your table.