Ever - i would leave the plants out 24hrs a day 365 days a year....
Sarracenia and flytraps are full sun (means just that, full sun!) and temperate, meaning they go dormant
im not sure if someone has gone over this in a previous post as i have not the time to read over it all at this point, but these plants generally grow from late spring into early/mid fall and are dormant between those times over the winter etc...
in order for this process to occur however, these plants need to be outdoors, as inducing dormancy indoors is a royal pain in the $*%.
depending on where you are, there should be no reason to have to bring these plants in at any point, if they are in a big enough pot, they shouldnt die from a freeze unless its a severe SEVERE one...
ive had my plants go through 4ºF freezes for over a week and still come back in the following spring...
though now i generally place them in the shed if it drops below 20 or so for an extended period of time....
they are much more hardy than people let on to be....
the plants really do need this dormancy time, as it allows them to essentially "rest" for the next growing season...without the dormancy period, the plants will eventually weaken, and die...same goes as if the plants are not in strong enough light, they will etiolate, (stretch out for light, and weaken) and also, through this, eventually die from lack of sufficient light...