You would find having such a need in most Yii Projects. Your database needs a specific format to store date fields, while you may want to display it in different formats to the users on forms and other views.
Following on from international dates, I also wanted times in the local timezone and format. This was a little more tricky but I think I've got a solution. This is only really appropriate if you have an international app.
This Behaviour helps to view time/date/timestamp/datetime from db to local Date / Time / Date Time format and in local Timezone. And save into db in with db timezone and db format. You only need to include this behaviour in models where need this facility.
The yii2-field-range extension enables you to easily setup ActiveField range fields with Bootstrap styling. You basically can setup two attributes joined together like a single field with combined validation error block.