[support] Tips & Tricks while taking over a website

[Afan Pasalic]

I got a D7 website to take care of. Since the website is still "in charge" of the old/current/outside web development company, I don’t want to do anything on the production website to avoid any possible conflict with the web development company. 
I installed copy of the website on my localhost and trying to figure it out what they were doing. The website is rather complex with tons of content types, webforms and custom modules. 
Anybody already had exact or similar experience with taking over a website? Any tips and trick would be appreciated. 

Thanks for any help.