In my experience, skimping on error handling around edge cases will cause 1 to 3 orders of magnitude more time on support requests. In the worst case, I've seen

In my experience, skimping on error handling around edge cases will cause 1 to 3 orders of magnitude more time on support requests. In the worst case, I've seen an entire dev team spend 20% of the team on manually editing the database to patch over incomplete code. I saw this go on for 2 years before I upgraded to a better job. Management would never spare the time to fix the underlying issues because it wasn't adding new features. At another job, I spent an extra month (33% of the dev time) finessing the error handling to new application. In the first few months, a couple of issues popped up. The next six months after needed less than a day's worth of support request. I've never had an application run so smoothly in my career.