You may see a domain renewal letter arrive on your doorstep warning you that your domain name is about to run out and asking you if you would like to renew it. However if you look closely at the wording you will see that it is "now is the time to transfer and renew", this is because they can't automatically renew your domain name as it is not being held with them.
Should you fall pray to this time of scam, after paying their fees you would find that they will then ask you for an Auth Code for the domain name so that they may transfer it to themselves. This would put control of the domain name with them and not your current provider and as a result you could loose your services (email / website).
If you do not give them the Auth Code then nothing is done and your money is lost. So if you look at those options again ... risk loosing your email and web or write off the moneys paid as a bad experience.
Please do not fall prey to this scam ... if you receive any domain renewal you should contact your current provider to check your specific situation as only they have the authority to renew the domain name without any transfer taking place.