Overview, in conclusion:
Conduit doesn't protect against lime attack
-doesn't help with temperature
-doesn't help protect from drills and nails.
-wouldn't be a huge help if you had to replace a lot of cable. You'd be very lucky to successfully drag a set of new cables through much of my existing kitchen conduit without snagging on the L s and T s. Easier for an electrician in the future to rip everything out and start from scratch.
So it seems that conduit doesn't really serve any great purpose.
-It somehow encourages me to do a neater job though, to keep to the zones and think things through more carefully. Kinda looks like it ought to be there. So I'll carry on using it. :-)
Cheers
Tony