When can I Unstake from Lido?

Could you please elucidate the specific timing for when I might be able to unstake my assets from Lido? I'm keen on understanding the flexibility and potential limitations associated with this process. Is there a minimum staking period that I need to adhere to, or is it a case-by-case basis? Additionally, are there any penalties or fees involved in withdrawing my staked assets? It would be helpful to have a clear understanding of these factors before proceeding.