If you have a domain name registered, you need to renew your registration every few years. You can generally ask for a 1-3 year cycle.

If you like your DNS registrar, there is no need to switch.

Today I received paper mail from a company called iDNS. I'm not a customer. The mail looked an awful lot like a bill.

"You must renew your domain name to retain exclusive rights to it on the Web, and now is the time to transfer and renew your name from your current Registrar to Internet Domain Name Services. Failure to renew your domain name by the expiration date may result in a loss of your online identity making it difficult for your customers and friends to locate you on the Web."

Sounds scary.

You are probably already guessing that their prices are much higher than a random sampling of other registrars. You would be correct:

Nice deal, right?

I recommend you avoid doing business with them -- for anything. A company which will try this, I would not trust for anything else.