Storing all the messages and global strings in one place will make it easy to manage them and to keep the applications in the same style.

Catch(SqlNullValueException sqlex){Response.Write("The value cannot be null.");}
❌ Bad example - If you want to change the message, it will cost you lots of time to investigate every try-catch block
Catch(SqlNullValueException sqlex){Response.Write(GetGlobalResourceObject("Messages", "SqlValueNotNull"));}
😐 OK example - Better than the hard code, but still wordy
Catch(SqlNullValueException sqlex){Response.Write(Resources.Messages.SqlValueNotNull); 'Good Code - storing message in resource file.}
✅ Good example