There are usually broad professionalism expectations, but the day-to-day standard is heavily influenced by office culture, client environment, and the type of work you are doing.

If you are uncertain, err slightly formal during your first days and then calibrate. The principles in the consulting dress-code guide are a safe baseline.

The key is not finding one perfect outfit. It is having a wardrobe that lets you move up or down one level of formality quickly when the situation changes.

I started too formal for about three days, then copied what everyone around me was doing. Easy fix.