ERROR: "Could not allocate space for object 'X' in database 'Your Database' because the 'PRIMARY' filegroup is full"

After adding tracking information for an order, I clicked on the box "Set as shipped" and the following error was displayed on the screen.

ERROR: "Could not allocate space for object 'X' in database 'Your Database' because the 'PRIMARY' filegroup is full"

When I clicked back on the page, the order had been set as shipped.  So I clicked on the "Set as delivered" and the same error appeared.  When I clicked back on the browser, the order had been set as delivered.  However, the order was not marked as complete and there were no email messages that sent out to the customer.

Also, no errors in the Admin>System>Log

So I went to the following site and followed the instructions to fix the problem:

https://support.managed.com/kb/a132/error-could-not-allocate-space-object-x-database-your-database-because-primary-filegroup-is-full.aspx

My database size was limited to 25MB.  I set it to unlimited.  

I was wondering about database size and maintenance.  Am I suppose to regularly compact the database, or do anything to maintain it over time and keep it running smoothly as it grows?  

Thanks!

-Fred