Ain't that the truth. Mind you, I always cringe when the insurance invoice arrives, but everything else is lots of smallish costs over the year, and definitely worth it for what I personally get out of it. Take yesterday for example, I flew from Somersby to Caloundra, a short local flight on arrival to scatter a mates ashes after his 'final flight', had lunch with his wife at the surf club then flew back to Somersby. All in less than 11 hours., with around 7.5 hours in the air. Short of hiring a PC-12 from Bankstown, it'd be damn hard to find a better, faster way to do it.Personally, I don't consider the engine replacement costs or anything else other than fuel as a direct/regular operating expense. I might buy a carton of oil every 18 months or so, and some plugs when I'm getting close to the 100-hourly but that's it, really. Tyres will be bought when needed, though I always carry a spare tube in the hangar. My engine is (was) brand-new, and everything else I simply replace when the time comes, but to do a 'proper' comparison, they do need to be included in the total operating cost.