didn't know time capsule could reinstall programs. wonder if it can reinstall your leopard apps when you upgrade to snow leopard.
ok so,
#1 is best financially because you spend $2,700 every five years ($3,000 - $300).
#2 is the worse because you spend $7,500 every five years assuming you sell the old one for half price after a year.
#3 This is actually in between, assuming you sell it for 2/3 the cost you end up spending $5,000 every five years.
I suppose if you end up selling your $3,000 MBP for $2,500 after 6 months then you end up spending $2,500 every five years. Not bad if that's the case although you come to the lease or own debate where some people just enjoy owning their own car/laptop than getting a new one every now and then.
For cost benefit analysis, to do better than break even, do two things:
1) rent the machine with software you pick
2) use that to make money charging clients per hour, billable hours
This is what the world's largest non-book publisher has done who I worked for. During the late-80s until the early 2000s, this fortune 500 company would rent, let's say a Power Mac G3, loaded with a full suite of Adobe software and other titles, pay $1000 a month for the machine plus full 24/7 on site tech support, and at the end of the time period of rental, just switch it out for a newer machine, let's say a dual G4 Power Mac with all the updated software, and continue paying the $1000 dollars a month, forever, if you wish but going only month to month. We would rent out the machines at $24 dollars an hour and when we did simple graphics jobs which could be as simple as making a personalized Christmas card and taking out "red eye", we would charge the customer $90 dollars an hour, and this was fifteen years ago. Each machine in our arsenal netted us thousands of dollars each, every month, and we never had to buy a single piece of equipment or software, but only paid for the electricity to run the rented machines and paid for paper.
I also worked at the second biggest educational book publisher in the US and we also rented from this computer/software rental company, at the $1000 dollar a month rate for machine/software/support, but the net profit at the end of the day was not quite as big as the previous example. This was a few years later and the G4s/G5 Power Macs came pre-installed with Microsoft Office for Mac, Adobe Design Suite, Adobe Web Suite, every Apple software title, and Quark or about $15,000 dollars of software in a $4000 dollar machine.
Other than renting a machine, being guaranteed unlimited service and the latest hardware and software at no additional monthly rental cost, and charging people for the products you make with the machine, there is no easy way to profit from any computer.
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Personally, when I look at the fact one iBook netted me a couple thousand in its life on side jobs was not bad, however, the iBook was $1599, the Adobe Suite student edition was $425, so I just about broke even.