When it comes to 24 hour time switches I prefer electromechanical to electronic. I find the mechanical ones to be more reliable over the longer term -- less prone to failure due to mains surges, faster and easier to set (no fiddly menus), etc -- and 15 minute resolution is fine for my needs.

So, tonight I picked up some Arlec model PC627 at Bunnings for $4.95 each. What caught my eye is that the switch is double pole.

Hear hear!

Absolutely so GTC!
For decades back in last millennium I used electromechanical timers in basic control panels for pumps, generatings sets and so forth.
That was the sort that ran from 12dc or 240ac and had a dial that you stuck little coloured pin things, green to start at x hours and red to stop at y hours.
Farmers and land people could understand a mechanical dial marked in hours and bits of hours (1/4 hours) that went round and round.
If the power failed it was just like a clock stopped, twist to reset by your wrist watch and away you went.

Then the computer age arrived and the old fashioned clock that everybody, even me, could understand was replaced with the new DIGITAL unit.
Yep thats the one with a DIGITAL read out and 16 buttons that you were to "program" it with and 5 pages available on the menu read out so you could start your stock feed water pump to syncronise with the movement of the outer moons of URANUS and stop it in time to catch the transit of the Orion galaxy over a black hole, or something.

Farmer John said to me "what the f**k is this stupid thing?" on a commissioning job.
"No problems John, here is the manual, take a read of this and you will be up to speed in no time".
John, whose thumb covered all them little panel buttons in one go, just looked at me and hollered for his Grandson.

Well that's a compilation of the problems those digital timers caused me, the worst being that if the power failed, the timer lost its program by the time I got there and defaulted to zero, needing re-programming by the Grandson!
Oh said the supplier , you need the more expensive one with the 1 week BACK UP battery, but by that time it was too late.

Fred.