Stone problem. Stone put up silently.

I have stone problem since 4 years back bt not give me any problems my stone is in kidney both having very samll size 2 stone in left n 2 stone in right kidney having sizw 3.2 n 3.3 mm both. I dont have any problems due to my kidney stone ever since long time only placed into my kidney this stone n i did many time usg with kub all report comes notmal and doctor said ut stone in not creating any obstruction anymore dont need to any medical treatment only having enough water n also i dont have any bad habits like drinking n smoking so my question is that 1. If stone are placed to my kidney for a long time than its give any problems in future like kidney failure or something as plz ans me i dont have any problems due to my stone ever only stone put up silently.