Driving in summer on winter tyres

I have no experience of driving on winter tyres or using snow chains. I'm
going to be driving for some months in continental Europe and I'm wondering
which option to go for. If I opt for winter tyres, do I really need to
change them back again when spring comes? What will be the effect if I
leave them on all year?

Thanks.

--

Paul Rooney

"Rooney is one of these vandals and has done his utmost to help trash dl and the
other groups which he regularly crossposts to. He's created a false FAQ
and charter" (Chris Lawrence in uk.rec.walking)

"Also long time d.l. reader but never feel robust enough to post much,
especially since Rooney wrecked the group." (Rachel Sullivan in uk.rec.walking)

"Low life scum doesn't even begin to describe you. You are the most loathsome
individual ever to cross the threshold of d.l." (JK in demon.local)