If you wish to learn how exploits work, to help guard against them, then yes you should probably understand the programing that they are coded in
This comeing from a guy who claims he doesn't really even touch 'em...

A bit exaggerated. You will never learn how buffer overflows & things work with C or perl alone. Whats the point of learning C or perl, only to find you are limited to editing the source code of others without actually even knowing what a stack overflow is really all about... yet alone know what things like stack or heap allocation is in the first place. You'll never learn one dang thing about the programs you plan on exploiting... this is where grabing an assembler comes in.

mov EAX, 10 ;value 10 to the EAX register
push EAX ;to stack

When and how do we use exploits
I wanna know how they r executed and under what circumstances would they be ready for execution?
Uhhh how cute.
Whenever you want. Download, compile, run, & enjoy... shmuck.