You can write your topic however you want, but you need to answer these questions:
**What do you want to achieve?
I want to know is it okay to use only few remotes events (or functions).
What is the issue? Include screenshots / videos if possible!
When I use remotes event for server side to client side (FireClient → OnClientEvent) then can I use same remotes for opposite, client side to sever side (FireServer->OnServerEvent)?
You can do this if necessary. I’m not sure in what scenario you would do this unless you want to put everything into one event. You can use a RemoteFunction for most cases, but you should send it from client to server.
It’s perfectly fine to. As others said, it’s completely fine to do so and it will not be harsh on performance. But I would only do it when absolutely necessary.