LOL @MoonShadows -

 I want to go work in my greenhouse, and I always stay out there longer than I plan, so I am practicing early today, but I feel myself "rushing" and I can't seem to do anything right!

 Hahaha - yup - I know that feeling exactly (not so much the greenhouse - any such structure would get destroyed by the westerly winds here - but I well understand the "rushing" thing.  I'm the same - it's like I have other-things-on-my-mind and I simply don't concentrate...   My best practice usually occurs early morning (early bird catches the worm kind of thing) - not unusual for me to be up and about at 5AM - at my age, I have trouble sleeping ! LOL )

 As to the original question - well - relatively fortunate here.  I have NEVER seen 20% humidity ( other than when I went on holiday to Greece and other Mediterranean countries in blistering-hot and unbelievably dry summers ).  Here, in the UK, and indeed in Scotland specifically, we are "blessed" with a lot of rain.  I wouldn't use the word "humid" to describe our environment (although on VERY rare occasions it could be described as such - but very rare - like a precursor to a thunderstorm or whatever)

  Even in winter - well - it's not super-cold-and-dry by any means, and within the house, I've never seen it (humidity) below 50.   If anything, due to our temperate climate on this island of ours, we're more likely to see it upwards of 60 RH.  Occasionally, in summer, with a blazing sun and glass windows all around, and playing in the "porch" (garden room/conservatory) yes indeed - it can get VERY dry - but that is specific and exceptional - and I rarely play there (unless it's "Play Music on the Porch Day" - lol - so like once a year)

  So, to answer the OP question - ALL my instruments are normally kept out of their case ( two of them don't have a case anyway ) - and that's of course when I'm at home.  If I am travelling, sure, I'll take one of my fiddles with me, and it will be cased - but - no real need for a case humidifier or anything like that - quite un-necessary (in this part of the world, unless you're paranoid about it I guess ).  Of course I understand the effects both thermal and humidity variations can and do have on such an instrument - and I completely understand the concerns of others in more "extreme" environments (even if man-made via certain forms of CH)

 I guess, on this one, I'm just "lucky" !    

 Good question though, Jim, and helpful to many folks I would imagine !

damfino said
Sounds like I need to move to Scotland so I can leave my fiddles out year-round.   

@damfino - Any time my fiddler friend - any time - we'll make you most welcome - and as it happens - I had forgotten about posting this link when we were chatting on the "Traveling Rosin" thread - so thanks again for the Baker's Rosin - and here's the tune I had in mind as a small "thank-you" ( no, it's not me playing, so it'll be fine - and indeed it has a score to go with it from Peak Fiddler - so here yah go Mandy !!! ) just for you, from Peak -