We use phrasal verbs and idioms a lot as native speakers. You might use phrasal verbs more than you actually realize talking about everyday life : get up, hang out with friends, clean up the house etc. Some idioms may be more 'relevant' to you based on your job/studies/lifestyle etc. but there are many used in everyday life. Examples: a piece of cake = easy It's raining cats and dogs = it's raining heavily to cost an arm and a leg = very expensive There are some resources such as 'An Idiom a Day' that you can find online to help you get started.

context is everything

The reality is that you have to ask English speakers. It does vary between countries, but if there is an idiom, you can be sure it is used. Some of the more common ones: It costs an arm and a leg. Get your act together Hang in there. It's not rocket science Let someone off the hook. Call it a day. There are quite a few....you can just Google them.