After a few years on similar metformin dosage (3 x 500 per day) I discovered the LCHF diet. I also discovered the 'con' about statins, and resolved to get off both. My switched-on GP has changed his mind over the years and agreed that the statin for all argument is now well and truly debunked by many except of course by Big Pharma.
He recommended I wean myself off both slowly and that this was up to me. At no point he advise me to come off. It was my choice. I stopped stains over a month by taking my 5 Mg daily dose every second day. Once off the statins I reduced my metformin by 500 Mg at a time over 2 months until I stopped completely. During this process I took daily blood sugars and plotted them on a graph noting the significant dates when meds were reduced. I couldn't have drawn a straighter line without a ruler. There was no significant drop or rise apart from the odd (naughty) spike. My blood has remained the same since, I have been off them for about 4 months now. This convinced me diet was all I needed, and of course the 20Kg weight loss helped me feel so much better.
I still take an aspirin a day, and a beta blocker and blood pressure med but that is for a 10 year old bout of angina, rectified by 3 stents. I have no plans to come off these meds as I feel they are contributing to my wellbeing and potential longevity.
In short I guess it is how you feel about taking meds forever or being med free. I still get all bloods done every 3 or 4 months just to check all the other stats, not just glucose.