What if we were talking on DUAL Core Desktop VS. Core 2 Duo Desktop which would last long and which is more economical to use on a computer shop business?
Consider life span, maintenance, availability of spare parts after several years etc.
RockmanXXV, sir your choices got simplier. It's Core 2 Duo.
The Core Duo is being slowly phase out.
They're both practically the same except, Core 2 Duo came out later. And has a different architectural structure to its silicon that gives it a more sophisticated processing abilities. Which gives the edge to the Core 2 as performance/speed is concern, but not by much. And is available in 2 diff. technoligical node flavors. The .65nm & .45nm, if you wanna go technical now. Typically the .45nm node consumes less energy, in turn produces less heat. Which explain why the Core 2 Duo line won the battle for Intel against AMD. You bet ya, AMD is coming back with something new.
As far as lifespan, maintenance & etc... it's hard to predict. There are too many components to consider. Which means, there are too many variables. The one thing I can tell you is, it all depends on how the user/users uses the machine.
For example: Too many people who uses a Flash/Thumb Drives, don't even use a procedure to eject the drive when they're done. In turn, it create an error not only in Windows but to the built-in Apps on the drive too. As errors accumulates, it de-stabilize the Windows which makes the OS unstable. Now do you get my point?
As fas as availability, spare parts & etc. You can't stop progress. Everthing changes as new technology arrives. Core i7 came out sometime ago. Now Core i5 is already available. Soon, the Core 2 might be phase out too. It's just the nature of technology.
Just buy what your budget will allow and worry the rest later. The lifespan of a computer is about 5 to 7 or 8 years. I'm not talking 'bout PC dying here. I'm refering to the age of a PC. By that time your PC is old and it's time for an upgrade or replacement. Depending on whether it is still serving you well or not.
But that's when you typically replace a PC.
I'd advise you to get a Battery Backup for each of your PCs. Trust me, it'll save you a bundle in the long run. Especially the electrical current there is pretty much unstable, not to mention Blackout occurences. I hope these helps. Good luck chief.