So always make sure that there is a manual renewal option and that you can change your options easily for renewal and payment long before the renewal dates.
[edited by: Webwork at 10:09 pm (utc) on Feb. 3, 2009]
[edit reason] Removed specifics about different registrars. See Charter [/edit]
I agree: If your domain names really matter then you should always know "what the deal is", including how the renewal process occurs.
Also, assuming you are a fan of automatic renewals (I am) then it's imperative that you keep your credit card info up to date.
I am moving all my domains under 2 registers one I have my active sites under the other inactive sites with my hosting company. I have tend to visit the register more often and stay informed of when my domains are expiring or possible terms of service changes that can happen without notice.
Sometimes my credit cards are kinda full so it best me do it myself. :)
This as well lets me decide if keeping the domain name is worth it now and or let it drop. I have let 5-6 go in the last month.
And make sure that you white list the registrar in your email but keep your own diary of renewal dates. I have seen people loose their domains because the renewal notice was spam trapped.