I just buyed a new guitar for 2000$ and I want it to stay perfect for a long time so I would like to know in what kind of conditions I should keep it. I have an hard case if that help... Should I buy a humidifier? What is the perfect humidity, temperature etc...


Tsss, it's a Jackson Sl1 for people who want to know!
Simply put: if it's an electric guitar....don't worry.

They need very little attention - as long as you don't hang one directly above a radiator or whatever you'll be fine. Guitars which are nitro-finished can be damaged by sudden changes in temeperature (eg. getting to a very warm gig after walking in the snow), but most Jacksons have modern polyurethene finishes so there's really no cause for concern.
Take care of that axe!
TY very much bud I can now go sleep without worrying about that! (Hoping you didn't lied to me because your an internet psyco...? are you?)