Yes I have MGUS; was diagnosed 23 years ago in 2002. It is truly a waiting game.
While my M spike and FLC lambda have gone up, they are reasonably stable. My previous Mayo hematologist (who retired) wanted bloods drawn every 3 months. My current hematologist is more relaxed about all of this and I have blood tests every six months now. After 23 years I do not get nervous anymore waiting for results,
I guess time will tell. I do not have symptoms that I know of.