I just used some of my Christmas money to buy a lovely new case for my violin =] Something i'd been wanting for ages (as some of you may have known) but didn't expect to afford until well into next year!
It's really nice - a black rectangular shaped one, with a compartment for my shoulderrest so i don't have to squeeze it in amoungst the scroll anymore! xD It looks like a nice safe home for Fidelio, + has space for 4 bows and has... a hygrometer?
Ok, i have a vague idea of what it is
But please explain more of what it is?

My old stentor case i carried him round in didn't have these fancy things!!

It tells you the humidity level so that you can gauge whether you need anything in the case to keep the humidity level stable (ie: too dry environment you can use 'Dampit' or similar humidifier to add humidity)

There's one in my case too.

What level does it have to be at to need a 'Dampit'? What's the average reading?

Those Dampits or humidifiers come with a little chart to measure the humidity level in your case. They'll mark out below which level you need to increase the humidity level in your case.

I find that if there is a hard frost for a few days the humidity can go down to 30% or even 25%. At the other end of the scale it regularly goes up to 98% here in the west of Scotland . (This is going by the hygrometer on the wall - I don't have one in my case). Ideally, i.e. for museums and so on, the level should be 50 - 60%, but you are unlikely to get that very often here, and I imagine that Wales must be similar.

Dryness is more of a problem than damp, and keyboard instruments are more vulnerable that strings because their frames are so rigid -- the first time for us that the humidity went below 30% the soundboard of our harpsichord cracked, as we knew it would. (Doesn't make the slightest difference to the sound.) But on a violin all the wood can move enough to even out stresses.

TBH I don't think you need to worry very much about a violin that is being regularly played. Unless you live in a modern house with electric heating turned up high, I don't think you will need humidifiers.

....unless you regularly take your violin abroad.

I didn't think i need to worry much about it either... it's played reguarly, every day. I don't take it abroad either really...
Though it does come out in the cold a lot - i take it to school most days to practise in my frees and breaks, and recently it's been SO SO cold that that worried me x_x But then any case should protect it more or less from temperature changes generally shouldnt it? We also have the central heating on a lot in our house - but only in the winter as it's been so cold this year. It'd be fine at any time except winter XD!

Um....no, not really - cases only protect to a certain extent. I keep having to tell my students about leaving their instruments in their parents' cars during the day so they don't have to lug them about at school. No case will stop them getting too hot / too cold after a while. Better to take care where you put it / store it rather than rely on the case.