How to store lots of small text in a SQL Server database?
Because this is a log of sort, and you have space limitations on your database (due to your Express edition) I would recommend either archiving your historical log data away from the database or simply deleting data that is older than a certain elapsed duration threshold. It is not uncommon to have an agreement that history is retained only for a certain time period. Just ensure this is covered in your service level agreement provided it pertains.