IR Spectroscopy functional group absorption ranges values yaad krni or no?

Lwk mene pura saal waise hi zaya kia and now ab exams sar pr agay I opened the chemistry book for the first time, abhi pehli dafa parh raha ho ye chapter cuz most log keh rhay thay it's important and is se sawal ain ge, I just saw the table and wanted to ask k do we have to memorize the values of the common functional group and what frequency range absorption they have of I.R? and don't alot of them have a similar value to how to go past that confusion Kindly let me know if you have any idea