Exactly. The DPF has a finite life, I think (if I'm not mistaken) that it's reported to be viable for 2500 regens and then it's done), so no matter what or how you maintain your tractor, at some point you will be faced with an expensive repair. The other issue is of course regen frequency. Not being a Kubota tech. I don't have any idea how the emissions components determine the DPF lifetime, if it's by count of regens by the ECM electronically or by sensing the restriction of flow of exhaust gas through the DPF, but be assured, at some point, the engine will derate and the cannister will need replaced.
Being retired from the Class 8 heavy truck arena and having worked at a Western Star dealership for 28 years, I've seen first hand how that replacement plays out because just like the Kubota (and other emissions compliant Tier 4 final engines (Deere or Kioti or whatever because they all use the same basic emissions components to achieve the emissions requirements), the byproduct, the burned ash in the cannister is considered a hazardous substance and must be disposed of in a specific manner, not tossed in a garbage can and secondly, the cannisters themselves must pass a rigorous inspection to even be cleaned and at the dealership where I worked, less than 5% passed. 95% were destroyed and replaced with new and they aren't cheap.
I think Kubota is banking on the fact that most original owners won't put nearly those service hours on their machines, at least not the original owner but some owner will and some owner will be on the hook for a DPF cannister replacement. That is a given.
You can take the best care of your unit but the bottom line is at the point of derate, you will be replacing the cannister and most likely other components in the emissions system as well, if, it makes it DPF cannister capacity that is, because the failure rate of the associated components is pretty high as well.
How it works and consider yourself fortunate you don't have a higher powered unit that has not only a DPF cannister but DEF injection as well. DEF dosing issues are another can of worms.
All about clean air and the enviroment as you as the end user gets to pay for it.
Why I'm perfectly happy with my Pre Tier 4 Kubota's. I can with some black (particulate) smoke and I like that smell of combusted diesel fuel.
...and why Pre Tier 4 tractors are highly valued. No issues other than routine ones.
The engines are a time bomb that get closer to a huge repair bill with every regeneratioin.
Being the industrious people we are, most everyone wants to do a 'delete'. Problem is, you cannot just unplug the sensors and negate the emissions hardware. The emissions systems are all married to each other so if you 'delete' one aspect, the engine's ECM will go into derate. How it's designed.
I maintain that of Rudolph Diesel were alive today, he'd be shocked at what emissions engineers have done to his efficient and reliable engine.