My current Credit Card which is linked to my PayPal account is going to expire in next month. I already verified my PayPal account by linking that CC. Do I need to verify or link another CC again to stay verified? Is it a must to link another CC? ( I just use my paypal account to receive money and I can make payments using the PayPal balance without any other payment source and currently I withdraw the PayPal balace to a USA bank account )
Your bank will send you a new card before it expires. Once you got the new Credit Card just go to Paypal and update the new card.
As long as your account verified, it is not necessary to add new card as from my personal experience! Verified my account using VCC back in 2010 and card was expired in 5 months have no issue since 3 years now. My account doesn't carry any card since June 2010 and account is still verified!
Once you've verified your account, I don't think PayPal will ask you to verify it again unless and until you need to send money from your credit card. I'm an Indian user and this happened to me.. My card expired but PayPal didn't ask me to verify again... But after 1 month, I've added another card as being an Indian user I can't send money from my PayPal balance...
Once its verified they will not ask again to verify unless if there is a strange transaction and paypal wants to know the reason for any particular transaction then they might ask to verify and in that case if CC expired then its a problem.