Agreed, but I have never seen anyone complain because they bought to big of a machine.
(unless they have to move it.)
It is always that it isn't big enough when they complain, or that they didn't get some option they thought would never be needed. I also know that the common thought is that; "if I buy the small one, I can always sell it when I need the bigger one and use that money for it."
I have never been able to sell any thing that I bought the "Small stuff" first. I always say I will use it, and then set it aside for another project. I might be a half-millionaire if I actually sold the stuff I don't use. But that would mean that I had to find it all again.
Nothing like having a 9x20" lathe and then realizing you want to do some work on a gun barrel that is 24". Then saying to myself that I should have got the 30". Instead of wishing forever, I found a great deal on a Southbend lathe that would handle it and bought it. Don't regret a thing.
Really, were talking about $200 to $300 here. Not something like a $200k Bull Dozer so you can level off a driveway once.
Regardless, if I want something bad enough, I will work hard enough to get it. My wife doesn't give a flip what I buy as long as everything is paid for from the start.