Read today some info that recaptcha gives you Token. The token is active for 5 hours on the server. The used token goes to some blacklist for 10-11 minutes. After something like 10-11 minutes you can reuse the same token, for up to 30 times per 5 hours. What's important - is not to touch the Token before the 10-11 minutes pass. But you can create multiple tokens, and use them with "schedule".