There are many variables on that one. It depends on the tractor and how you use the tractor. The dealer will give you the impression they can be used indefinitely. I traded my truck at about 50,000 miles rather than deal with the expense. I was already on the third turbo. Lemon? I don't know. I bought a Kubota L2501 so I could avoid computers, particulate filters, and anything else they might choose to throw at me. It will do the job nicely for me as I only have ten acres. A larger tractor might be nice but good late model used tractors are scarce around here.
If you are using that size tractor for 10 acres I wouldn't need anything bigger than an RK 24 for 3 acres of grass to plug, sow and put out mulch along with scraping a couple of driveways. Let me guess you had a Ram?
Each tractor owner will have a different experience with component service but consensus is 3,000 engine hours tractor DPF service life.
The average residential compact tractor operates sixty engine hours per year, according to industry surveys.
3,000 hours DPF Life / 60 hours = 50 years of residential use prior to DPF replacement.
Diesel Particulate Filter supersedes tractor muffler.
At some point in time DPF needs to be replaced.
At some point in time tractors with mufflers need the muffler replaced.
I purchased my Kubota L3560 in January 2013. Now 1,600 engine hours on the clock. No DPF problems at all.
Tire wear and tire replacement will cause as many headaches and more expense than DPF/DOC for most long term compact tractor owners who read and comprehend their Operator's Manual. I am shopping replacement front tires now.
Can you just removed the DPF? I would have thought with all the computer controls on the engines it would go into some type of limp mode and not run with the dpf being removed.