When CPU usages shrink?

Question

I created EOS mainnet account and I tested some transfer commands.

Each time when I typed transfer commands, my CPU usage increased about 2ms.

So I staked EOS to my CPU constantly, and I think there's no difference with "Fee"!

In my thought, after a few times ago, I will be decreasing little by little, but after a few hours later, It didn't changed.

In another steemit post (https://steemit.com/eos/@leordev/eos-ram-and-bandwith-analysis-airdropping-steps-on-junglenet), in reply, dan says that

"Once people claim their tokens you get the ram back" (It's not for CPU's, but... anyway!)

So, my questions is,

Q1. Can my CPU usage shrinks when I executed transfer commands? If can, how can I know when is that time?

Q2. What "claim their tokens" means in dan says?

Answer 1

Q1. Can my CPU usage shrinks when I executed transfer commands? If can, how can I know when is that time?

Your CPU usage resets after an average of 24 hours.

How long is the reset period of the cpu bandwith?

Q2. What "claim their tokens" means in dan says?

Dan means that once people move their tokens, they'll become the payer of the account balance row in the smart contract. Because they are the new payer, the old payer is no longer a payer and his RAM staked is now unstaked.

CPU and bandwidth comes back easy enough, so you can get pretty wild with it, RAM however is a different story, you cannot unstake RAM at anytime like you can CPU and bandwidth. This is because RAM can become commited to records in smart contracts, e.g. the eosio.token contract where a piece of RAM is used for every account balance. Until that record is destroyed or someone else is paying for the RAM, that RAM cannot be unstaked.

Answer 2

Copying the comment from @nat as an actual answer.

Your CPU/NET recharges over 24 hours:

static const uint32_t account_cpu_usage_average_window_ms = 24*60*60*1000l;