VARCHAR and indexes

I recently got advice from an Informix consultant that any character field that is 18 characters or longer should be defined as varchar. He said that this would result in lots of saved disk space. He made no mention of indexes and what effect varchar has on indexes. Can someone tell me the rule of thumb on when to use varchar and when to use char? We have Informix Dynamic Server ver 7.24 for Unix. We do not use 4GL or BLOBS. Thanks -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own