It is always advised to renew the web host services
at least 15 days before it is due for expiry. The host normally sends a reminder notice email daily to the address provided by the client a few weeks before. At times when there is a credit balance with the host, the renewal is automatically done till such time that the amount gets adjusted. But in case the client does not renew in spite of the repeated reminders, the account gets canceled and the client does not get access to the files and the website. The rules are same for domain registration renewal.