I renewed each app since I have been using IPB and its apps, what is almost 6 years. But in last time I have feelings that it's not needed. I do major upgrade maybe 1-2 times per year and apps are updated only sometimes. I need support only very occasionaly and there some apps with which I am disapointed with progress (not official apps). On spring 2012 I'll finish studying at university and then maybe I go away. When I'll stop all renewals can I renew it at any time without penalty to regain access? For example after 3-4 years.

Simple answer is yes.

When your license is expired, you can continue to use what you already have and are already using, but to progress beyond that or to get support, you need to renew at the renewal rate. No penalties.

Yes, thanks.

How to stop renewal? Simply remove credit card info?

Do that and also submit a ticket to Account Assistance/Billing to ensure that any renewal invoices won't be auto-charged.

OK, I remember it. Thanks.