How long does it take to unstake Aptos?

I'm just starting to explore the cryptocurrency world and have recently staked some Aptos tokens. I'm curious about the unstaking process, particularly how long it typically takes. Could you please provide some insight into this? I've heard varying estimates, so I'm hoping to get a clearer understanding from a professional like you. Is the unstaking time fixed, or does it vary based on certain factors? Also, are there any penalties or fees associated with unstaking? I'd appreciate it if you could break down the process for me in simple terms.