Think of it this way. If I didn't have the motorcycle, then I would need to purchase a new truck within the next 5 years. With the motorcycle, my current truck will last another 15 years or more.
Well, there is some (wishful?) logic there but how much does 15 years of repairs, insurance, registration, tires, chain, etc. for the motorcycle cost? And remember that after 15 years of use and many miles your motorcycle will need replacing and the old one will have negligible value. As will the ancient truck by that time, so depreciation of both has to be included as well. You can push your expenditure back, but there is an ongoing annual cost to that which must be added to the total cost of truck replacement when the time comes.
I still have not seen a way to parse these figures to show an economic advantage to supplementing 4-wheel vehicle use with a motorcycle. Fortunately that's not why most of us own one. Or two.
(BTW, I'm guilty of this magical thinking, too. I put on my $200 helmet and $250 riding outfit, jump on my registered, fully insured, expensively farkled $4000 bike and ride down to Costco instead of driving, saving probably a whopping $5-6 in gas. AND I FEEL GOOD ABOUT IT!)
I have a 2007 Accord EX-L Nav with 182,000 miles on it. The NAV unit took a dump last fall (I think the DVD laser in the trunk unit is shot... too expensive to replace). I just use my Garmin Nuvi if I need NAV now.
My son drives my 2004 CRV EX which now has about 235,000 miles on it.
Other than normal "wear" items (oil, brakes, tires, etc.), only replaced the A/C compressor at 185,000.
1995 Toyota 4-Runner 104,000 miles 1994 GMC 4X4 SUBURBAN SLE 68,000 MILES 1994 SAAB 900 101,000 MILES all are rust free GMC never seen snow and this is the first winter for the saab all ways stored in winter.1979 Suzuki GS850 9000 MILES Like new.......