custom scripts vs built in components

[frank tangle]

making a thread so i don't interrupt current conversation
so hi, i'm new to unity, a long time ago made a game using pygame (basically a 2d platformer), and decided to port it to unity cause i want to continue working on it and don't really like pygame so (sorry if it's a dumb question cause i just started with unity and don't know much about gamedev)
i'd like to know if it would be better to use built in unity rigidbody 2d for gravity and collisions or to write my own scripts for those things
in terms of optimisation and in terms of compatibility with my game cause i'd like to have underwater movement and what not, would it be a problem with rigidbody or am i just reinventing the wheel?

[wispy loom]

You generally use a combination of both

The built-in components solve common hard problems, like making something respond to forces and colliders

You write your own components to create logic for your game

[frank tangle]

thanks, but i'd like to know is there a reason for me to make my own alternative to existing component so that it is more customisable for my game?

or they are already customisable enough and i don't need to do that?

[shell mirage]

I'd start with Unity's collider and physics engine. At least create a test scene and experiment with what they provide with your custom components (scripts). It's much easier to build on top of theirs instead of writing your collision and gravity . . .

[frank tangle]

nice, thanks!