Jordan wrote:

I'm getting a workshop built, and can make a choice to have 3 phase
power connected.
I'd like to buy some ex-factory machinery.
Q: Is it worth the expense? Or, with electronic solutions to running 3
ph. machines from single phase power, is it not worthwhile?

That depends on what the utility offers, how big your shop is and
whether it's a business or personal shop. Three phase power will
generally put you on commercial peak metered rates vs. kWh based
residential rates. If your machines are all fairly small, there aren't
too many and you aren't on commercial rates anyway, using VFDs or a
rotary phase converter may be more cost effective. If you have anything
over about 3HP VFDs used as phase converters become less cost effective.
You basically have to make a spreadsheet listing everything you intent
to put in the shop and then work up the initial and operating costs for
the different options.