Can I Unstake anytime?

Good day, I'm curious about the flexibility of staking in cryptocurrency. My question is, "Can I Unstake anytime?" I understand that staking involves locking up my tokens or coins to support a blockchain network and earn rewards in return. However, I'm concerned about the potential need to access my funds unexpectedly. Is there a specific timeframe or condition I need to be aware of before I decide to unstake my tokens? Are there any penalties or fees associated with unstaking, and if so, how do they compare to the potential rewards I might earn? I'd appreciate any clarification on this matter. Thank you.