do one's homework

do one's homework (to make careful preparations so that you know all you need to know about something and are able to deal with it successfully) —заранее хорошо, как следует, основательно подготовиться

...As far as I know, the company is undergoing some change in connection with the merger that was a real [sweetheart deal] with the company owner's cousin and the employees aren't happy with their present situation because lots have been made redundant and... —Ok, Ok, I see you've done your homework. — Насколько я знаю, в компании происходят кое-какие изменения в связи с ее продажей родственнику владельца на выгодных условиях, а служащие недовольны, потому что многих уволили и ...— Хорошо, я вижу, что ты основательно подготовился.

...If you’re paying high interest on a mortgage and you plan to stay in your home for a few years, consider refinancing. Be sure to do your homework to avoid closing costs that might make the move less attractive financially.