Much of it depends on the background of a company. If you are writing software for a large financial institution, chances are the HR department will ask you to

Much of it depends on the background of a company. If you are writing software for a large financial institution, chances are the HR department will ask you to wear business casual (or worse). In my experience in the east, middle-sized companies can go either way--some mandate business casual, others don't care. Again, in my experience, this is often related to whether clients are often visiting the offices. My current employer, with its tech leadership drawn from the Valley, has been incredibly flexible about most things. But we were recently acquired by a more established, traditional company based on the east coast. There are rumors that I'll have to start wearing something other than shorts and t-shirts at the office, but nothing has been handed down yet.