I know this has been discussed extensively, but I didn't see the specific answer to my question. And my avionics shop gave me an unexpected answer:
If I update my 2000 M20R with the part-vacuum driven vintage KFC 225 system and a Garmin 530 / 430 combo (WAAS) -- to a Garmin G500 system, how many data card subscriptions will I need for the entire system? Will I need 2 extra cards for each of the G500'ds? Or do I only need those if I want the Jepp charts? I am trying to figure out cost-of-ownership. I already have subscriptions on an Ipad and another handheld Garmin 695 with all maps and plates. So I really don't need yet another subscription to update.
If the G500 acts just like a regular AI and DG that it replaces, then I won't need extra subscriptions. That's what the avionics shop told me (don't need another subscription).
Anyone know the answer to this? Note that I want to maintain IFR certification of course!