In my previous job I was not allowed to wear jeans, sneakers or non button-down shirts, it was suit and tie. If it was to hot you where allowed to ditch the tie. When I started my present job I didn't know anything about the attire required so I showed up in my previous work attire. People had a good laugh that day! They show up in whatever they feel like, I have seen people in a plain white t-shirt, khaki shorts, white socks and crocs, the boss didn't give a care, but did had a joke with it. They say Europeans in general have a better taste in clothing, but I've seen worse.
I wear a button shirt, tucked in jeans or chinos and Chelsea (I love RM Williams boots) or chukka boots, for some casual but for work dressed up enough. A jacket or suit isn't required, but I normally have one available when I have face to face meetings.
We have a big party every year where people having a 25, 35 or 40 years anniversary with the employer get celebrated, some even come in their work cloths which is generally jeans and a jeans button down shirt....