Attribution becomes permanent the moment your code is redeemed. From then on that customer is yours for as long as they keep paying, with no cap and no expiration date.
Before redemption it works differently, and it is worth knowing. A click on your referral link is remembered on that browser for 30 days, and the most recent link clicked is the one that gets credit. Because that part is browser-based, the surest path is having the agent type your code in at signup, which works on any device.
Your referral link is formatted as https://ave510.com/?via=YOUR_CODE. Share this link with your audience. The /signup page also accepts a manually typed invite code if a referral arrives without the link.