2nd hand mac advice

[mrsurrey]

Hello,

I'm in the habit of buying the oldest 2nd hand iphone that supports the current operating system, which seems to ensure everything works as expected and is very cheap.

I was wondering if the same logic could hold for imac laptop computers? Do you know what the oldest mac laptop that supports the current operating system? Can they support windows office (excel/word/powerpoint)?

Thanks,

MrS