I had 2 removed 2 years ago, but since, 3 of those odd and nasty spots have been growing in my back which I'll have removed and analyzed Thursday.
They seem to grow in (curved) lines, a few inches away from one another - I also have 5 of them on one of my legs, though these are paler. One has been around for 7 or 8 years and others just appeared gradually but steadily over the last 2 years or so - scratch it off, it comes back... Thicker.
The fact that I've had some of them for years makes me optimistic. The fact that a few new/darker ones grew so fast, not so much. I'm well aware that it's just a matter of time before one grows that's not exactly harmless.
I don't think I've ever taken a day for granted, so this doesn't change things much. Still, I'd like a few thousand more years with my wife - and a couple of years with a SG standard and a big Marshall...