In the tens of thousands of miles I did in my old one, the only thing I had to replace was a rear wheel bearing (bought the whole hub for about £40 and just replaced that) and a water pump.

If you use decent fuel the injectors stay working for longer without failing apparently. I put the odd tank of V Power Diesel through mine and it never missed a beat. Mybe a BG244 can through the tank once a year just in case.