[Fina]

"You're welcome" can be translated to どういたしまして, but I have never heard this said before in a conversation.

Do Japanese speakers just hardly ever use it?

I understand it is a formal way of saying "you're welcome", but even in everyday life we say "You're welcome", even though most of the time people respond with phrases like "no problem".

What are some informal ways of saying "You're welcome" in Japanese?

Also, where I currently work I am always responding with "You're welcome", and never with "sure", "no problem", etc...because it could be considered unprofessional here.
So my last question is: If I am in Japan and always respond with どういたしまして, will people look at me funny?
I've gotten so used to saying "You're welcome" after "Thank you" (even with my closest friends) that it may be difficult for me to break the habit.