Here's a question for fellow developers. Since taking on programming several years ago and coding some pretty good apps for internal use by my employing entities, I've often been given to wonder why developing custom applications is somehow better than purchasing off the shelf ones. I scoured the web for a few good articles (here's one of them) but I'd be curious to hear from other developers directly as to how they justify their time and effort (or rather, how their organizations do). At what point or under what circumstances is the case instantly made for either scenario?