Generally, the doctor will order blood tests every few months (60 mo. interval for me). I am 70 and have had MGUS for 8 years; my kappa/lambda have gradually ramped up over the years but my M spike is still at the detection limit. I also get CBC (complete blood count) and autoimmune bloodwork. I was diagnosed with polyneuropathy 8 years ago, but it hasn't progressed (maybe more related to celiac disease in my case). Consider keeping a food log, just in case you have developed any food intolerances or other stressors.