RE: Worldbuilding

#2
Not really. World building for real world things is slightly different. I mean, the only time you want to describe something if it's important for context and if it's relevant. However, you don't have to say describe a garage because most people know what a garage looks like. Now if you need to describe the setting for atmosphere, you do that. However, if there was something unusual about the garage, you want to point out and whatever context that's needed for the reader to understand why it's different.

RE: Worldbuilding

#3
Depends on the setting kind of. But really the short answer is yes. You always need some worldbuilding. Like if your main character is a child solider fighting for blood diamonds in sub-Saharan African, obviously I'm going to need some 'worldbuilding' to understand things. Just saying 'real world' doesn't tell the reader much - that's a *really* broad net.

Even if your setting is more common, something seemingly ubiquitous like going to school, you still need to do some world building. Because while most people go to school, and most schools are similar, similar =/= the same, so you need to flesh out your setting to some degree, explain the things that make it unique (or the things that make it common).

Otoh if you're asking if its necessary to explain to the reader what a lamp is, or how electricity works, or what a car looks like ...nah. Unless you're purposely drawing attention to some feature of a physical aspect of your world, no need. People know what a lamp looks like, what it is, what it does. If it's something rare or exotic maybe a line or two explaining what it is some people don't have to google it in the other tab.
~writing is hard~