The vaults on ETH will harvest rewards every 3 days until the Total Value Locked (TVL) in the vaults grows. This is because vaults are designed to optimize yield for users, and harvesting rewards every 3 days ensures that users are able to take advantage of the highest possible returns. As TVL grows, the rewards earned by users also increase, as there is more capital in the vaults to earn rewards from. Therefore, harvesting rewards every 3 days until TVL grows is an effective way to maximize returns for users.