How much SOL do you need to run a validator?

I'm curious, could you please elaborate on the question of SOL requirements for operating a validator? How much SOL do I actually need to fulfill the role of a validator in the Solana network? Could you provide an estimate or a range of the amount required, considering the current network conditions and staking requirements? I'm also interested in knowing if there are any variable factors that might affect the SOL needed for validation, and whether there are any strategies or tips you could share to optimize my SOL allocation for validation purposes. Thank you for your insights on this matter.