Good question! Being vague about that is slightly intentional (we don't want to tempt you to ever think "if I ignore this for N more days I'll be off the hook...") but mostly for historical reasons. Anyway, to actually answer the question, since you asked, eventually means that after 30 days we will stop automatically recommitting you when you derail. So in the worst case you could derail one more time after 30 days. So something like 37 or 39 days is the worst case.
For premium payments, you probably know we have auto-canceling subscriptions which is exactly 30 days. So I think all-in-all we're drastically better about this than almost any other company.
Also if you have a high pledge cap and are worried about the charges escalating, we do start manually paying attention, definitely for any $810 charges. Ie, we're personally guaranteeing that we'll make sure you're actually alive before letting an $810 charge go through.