Why not use varchar(max)?

Question

I\'m a bit old school when it comes to database design, so I\'m totally for using the correct data sizes in columns. However, when reviewing a database for a friend, I notic

Answer 1

   It is somewhat old-fashioned to believe that the application will only pass short strings to the database, and that will make it okay.

   In modern times, you HAVE to anticipate that the database will be accessed primarily by the current application, but there may be a future version of the application, (will the developer of that version know to keep strings below a certain length?)

   You MUST anticipate that web services, ETL processes, LYNC to SQL, and any other number of already existing, and/or not-yet-existing technologies will be used to access your database.

   Generally speaking I try not to go over varchar(4000), because it's four-thousand characters, after all. If I exceed that, then I look to other datatypes to store whatever it is I am trying to store. Brent Ozar has written some pretty great stuff on this.

   All that said, it is important to evaluate the current design's approach to your current requirements when you are working on a project. Have an idea of how the various parts work, understand the trade-offs of various approaches and solve the problem at hand. Exercising some great axiom can lead to blind adherence which might turn you into a lemming.