Every two or three months !!! - hahahahaha - stop fretting - you seriously don't have a problem.Doesnt sound like theres much wrong with mine then just happens often every 2-3 months it will happen. I use diesel v power shell, put some cleaner in the fuel every 3 months also, gets decent runs... still having problems pffff lol
Mine regens around once a month that I know of.
It's all dependant on miles covered, how long the trips were and type of traffic ( stop start or flowing )
There is no FIXED regen interval - it all depends on soot loading of the dpf.