Are humidifiers necessary?

I live in Maine and will be receiving a Kala Travel Tenor for Christmas shipped from MGM. Due to vast changes of temperature from summer to winter, hawaii to maine do you think I need to have a humidifier in the case? What exactly does it do to help the uke? Keeps the wood nice and dry? Any info would be greatly appreciated. Thanks.

As soon as I get the uke I'll share it with the community, as there are not many reviews of the instrument.

humidity

instruments are built in a controlled environment, usually between 45-55% relative humidity. radical changes cause the wood to shrink and swell. if the wood dries out, the wood can crack causing serious damage.
ive never lived in Maine, but im guessing it gets extremely dry in the winter, and very humid in the summer. if you want your uke to stay in top condition, i would recommend the humidifier.

Great! I will take your advice. I read somewhere that it's fairly easy to make them too? Is that recommended or should I just buy some from MGM?

Maclay did a very good job of describing the issue. Here is an explanation of relative humidity. RH is a measurement of the amount of moisture the ambient air can hold at a given temperature. It is expressed in terms of percentages, for example an rH of 50% at 70 degrees F means the air contains 1/2 of the moisture that it can hold at that temp. When you reach an rH of 100%, the air is saturated and you get rain or fog. The issue with instruments is that cold air does not hold very much moisture. In the winter you may have a rH of 50% at 40 degrees outside. When that air enters your house and is heated however, the rH can drop to 25% or less. If you leave a solid wood instrument without humidifying it in that environment, it is not a question of if it will crack, but rather when it will crack. You should have a hygrometer in you house so you are aware of the rH and can humidify your instrument as needed. They are cheap and easily available and are your best insurance for a long lived instrument.

Brad

That makes perfect sense. We just recently discovered a crack in our Dad's guitar which is always out in the open.

A bit of perspective--In my New England 24 x 8 workshop, In August, I’m pulling over a gallon of water out of the air daily--Only to add it back at this time of year!! It's crazy, but it's New England!

~Stephen