I remember what it was like...
When I was told that I had thickening of the womb lining, the first verdict was that there was nothing sinister and it was thickening without atypia. Second time round it was the most senior consultant and he was the one that said it was the normal uterus of a 64 yr old.
He did recommend the Mirena, from the point of view of protecting the womb. (I have the risk factors of being overweight and never having given birth. Plus it turned out I'd been on the wrong HRT for my age!)
Had never had a coil in my life, but I agreed. I've been fine.
Oh...I'll add that when I was 40 I was given a laparoscopy because I'd tried and failed to get pregnant. (I reckon I just left it too late.)
The gynae that time found a small fibroid. 20 yrs later, there was no sign of the fibroid, so it must be that they can come and go?
From my conversation with the consultant, they remove polyps in the uterus when they see them, just to prevent problems. Apparently those a bit further down aren't a problem except they can bleed a bit. (I've also had some removed there.)
While I remember, I was first told about a polyp on my cervix when I was in my 40s. It was told that that was nothing to worry about - according to the consultant those don't turn nasty, but if they're removing polyps elsewhere they take them out at the same time to stop the bleeding.