Also, if you develop for multiple clients, projects don't bleed into each other. "Well, client X still uses PG 9.1, but I accidentally used a 9.3 feature, beca

Also, if you develop for multiple clients, projects don't bleed into each other. "Well, client X still uses PG 9.1, but I accidentally used a 9.3 feature, because thats what client Y uses."