What is EOS account optimization?
The EOS network stakes your tokens to generate resources that are used as payment to maintain your account and its actions. This system is called Delegated Proof of Stake (DPOS) and resource needs fluctuate based on individual account and network conditions. Additionally, EOS is used to purchase RAM for your account as well as vote for Block Producers (BPs) who validate the blocks.
If you're an advanced user, odds are you will not be reading this article. For the rest of us, DPOS can be quite confusing. The Optimize button in the Advanced Drawer will automatically adjust your resource stakes for you to maintain enough resources for making transactions. This button will automatically unstake from the network any amount over 1 EOS.
If you are claiming your EOS mainnet account from the pre-mainnet ERC20 EOS and have over 10 EOS you will see the balance as staked on the network. When the EOS account was created from the Genesis Block, the network automatically staked your EOS and you will need to use the Optimize Button to unstake. This is referred to as a Refund and will take 72hrs before the unstaked amount becomes available to use.