why must i wear thin ski socks?

When you learn to ski and get hire boots you wear nice big comfy ski socks, however, when you get your own boots you're told only to wear the thin so called technical socks. Can someone explain the thinking behind this as all i can think is that your own boots should be a closer fit so you don't need thick socks, but what if it's cold out?

Unless you're racing (or skiing on ice), I don't think sock thickness is much of an issue. More important is the sock shape; cheaper socks (especially tubes) will wrinkle up inside your boot and are impossible to get a consistently comfortable fit at the right level of tightness.

If you shop around, you can get technical socks in various thicknesses - so a Medium Weight technical sock will give you plenty control AND keep your feet warm...

And as you're off to Cervinia shortly (I think?), buy them out there: technical socks in Italy are half their UK prices.

Thanks for the tip, i shall possibly buy some more in resort. Yep off to cervinia in 9 days :) and can't wait, just hoping they get some snow there soon ;)