Permanent residency in Italy and Healthcover

Can anyone clear the fog for me.? The recent Referendum in the UK got me looking at the status of EU expats and I am more confued than ever. 
We retired  (early retirement) and moved to Italy permanently in  March 2013  (tax resident effectively from 01 01 2013    We applied for permission to stay at our local small commune and having proved we has sufficient  income etc and somewhere to stay  (we had been restoring a property since 2004)   We were each issued with a Carta Identita  valid until 2024 (70th birthday) 
This is my first query  -I had thought that they were issued for a maximum of 10 years!
2nd Query, we signed several forms but we do not appear to have been given  (pretty sure I have not lost them) any Permesso di Soggiorno papers  unless the commune hold them.
3rd query  - Since we arrived we make annual contributions to the Healthcare system  of around 395 euros each (no problem as far as I am concerned as it represents good value,  but I often see other people on forums saying they either make no contribution or have been told to get private cover ).     We were initially given two paper cards valid for 2 years because there was some issue on the system of our address as whilst the house was uninhabitable our Agent used his address to register for us, but have since been to the Agenzia Entrata , sorted all that out and were given plastic Tessera Sanitaria cards valid until 2021 .  Why 2021 I have no idea  (4th Query?)   
We pay all our taxes via our accountant who is also the commune accountant and our property is our Prima Casa as we sold up in England and use our daughters address as our UK postal contact.

Given all the kerfuffle over leaving the EU would I be right in thinking we still need to apply for permanent residency after 5 years  in 2018 (is that 5 years after being tax resident Jan 2013  or 5 years after May 2013 when we applied and were given ID cards?)  There seems to be no hard and fast rules as to how regions and communes work. I am as confused as ever.

As I am sure you know, rules change quickly.  If they issued you an ID card valid until 2024, then it is valid until 2024.  As for the Permesso di Soggiorno, did you actually submit the application form?  That is required in order to receive one.  Although this is post-Brexit, at the time you moved to Italy, I do not believe you were required to apply for a permesso, only register residency with your Comune.  I don't believe anything has yet changed on that, but if you're concerned about whether you should apply for a permesso, I suggest you talk directly to the Questura.  As for your health card, again, they are valid until 2021, but I would keep an eye on any changes that might occur due to Brexit.  For example, non-E.U. citizens are required to renew their health card every year.  It is going to be a long while before they get all of these issues straightened out.  As for the E.U. permanent residency card, I would think that you will be eligible after five years of having full residency in Italy and are able to show that you've paid Italian taxes each of those five years.  The Brexit situation has churned up a lot of questions that have yet to be answered.  I recommend that any of the questions you have be posed to the relevant office in question.

I can answer your first question. I just received my Carte d'Identita and the expiration is 2027. So maybe the laws have changed. Can't answer the permission question because I don't need one so have no idea of the process. Also just received my Tessera Sanitary but it has no expiration.

As for the Brexit issues, be aware that Italy may be facing this question as well in the near future. This latest referendum vote and political upheaval has many Italians thinking this way or at the very least moving back to the Lira.
Vincente