I have problems understanding when you will have to send a request from the client to the server, and server to the client. Can anyone give me specific situations when you'll have to do this?
If you're talking about RemoteEvent's and RemoteFunction's, ect.. You'll probably use them for all sorts of things, like messages, telling the server the client's just done something (Like in a minigame gone AFK so the server can not counter them into the round). I can't really think of anymore off the top of my head but I use them for 70% of my game's functions.