There is no need for you to renew your account manually. Any account which is still active on your renewal date will automatically renew. This includes both monthly and yearly accounts.
If you do not wish your subscription to be renewed, close your account before its renewal date. You can close your account within the program or online by clicking on "Account" and then "Cancel Account." For more information regarding accessing your billing, check out the Purchase or Upgrade Storage for One accounts article.
If for any reason you are unable to close your account, contact Support at support@spideroak.com.
Please keep in mind that unless your account is completely closed, you will be billed automatically. Uninstalling SpiderOak One does not cancel your account.