I am building a couple custom themes from previously designed and developed sites. I developed them and will be maintaining as well. As I am sort of new at custom theming I always hear that I should put the content in the editor so it's in the database in case of a theme switch.

I am setting up these sites using advanced custom fields so those areas are lost on a theme switch already. If I have no intention of putting these themes out for use or switching do I need to be that concerned about making sure they will work on any theme?