Its an impossible question to be answered if you tell me.
Marms occur in a whide range of the european continent being offered many different conditions depending in latitude, altitude and proximity to the sea.
Thus, we have to take in count that the vast majority of the newts on the hobby are old inbreed descendants from very suspicious origins, mixed populations and even I've heared of hybridization with pygmaeus. Its a chaos of a newt in the hobby sadly. I've looked at marms that were starting not to look like marms but like queers.
Spanish and French marms have their own ways of living. Here in Portugal I've studied some of them very closely and as far as I can say from the places I know them from, they are:
1º A very very terrestrial newt.
2º They dont have no hibernation
3º They dont have no aestivation.
The newts live from May to September in cool water body masses that they search for breeding purposes. They usually come out to land at night. They seek for land every time they can. Then, they are strictly terrestrial living under huge stones to around 1meter under the soil from September till May next year.
Resume: 5 semi-aquatic months used for breeding and sometimes with terrestrial behavior during night & 7 fully terrestrial months.
If someone had to ask me what I think, I think these animals are strongly terrestrial beings using the water only to lay eggs or courtship a female. The rest of the time is land time.
As for the juvies they wont even dare touching water till they are 3 years old and they usually live far from it in a strictly fashion terrestrial behavior.
Cheers,