varchar(max) vs varchar(255)

Hi guys,

I'm new to MS-SQL 2005, I will ask you a bunch of questions and I hope I will not be too boring hehe !

I learned that in MS-SQL 2005, you can now use varchar(max), my question is why not always use varchar(max) since it will automatically use only the space needed ? Is there an advantage in specifying a size other than max when you use a varchar for an entry that can vary in length alot ?

Thank you very much,

Konnan