Upstream Problems
EGR , pressure sensors , injectors , air leaks , maf , turbo and whole host of other problems can easily cause your DPF to block. We often repair cars that have a DPF filter cleaned or replaced elsewhere only for the filter to block within a matter of days or weeks due to an underlying issue upstream
Age of filter
At some point the filter will start to break up , this happens in about 10% of all the DPF filters.Typically with over 200,00km on the caror where lots of shorts journeys with excessive regens. Basically besouse the filters goes through hot and cold cycles it eventually craks
Driving style
The way you drive your car often leads to the DPF blocking .Short journeys switching the car off whilst its performing a regen (DPF light comes on and people switch the car off despite the handbook advising against) Normally driving style affects the earlier DPF filters more , pre 2000 cars