RafterGirl,
I would point you to the Ukulele Review Site (By Hawaii Music Supply/The Ukulele Site):
http://www.theukulelereview.com/2017/01/11/what-every-ukulele-player-should-know-about-humidity/
Here's the deal: while I do believe that The Ukulele Site wants to sell you a ukulele, I don't believe that they are warning about humidity with the intent of selling humidifiers, and I do believe that they have seen ukuleles come back to them, cracked, as a result of customers not caring for their instruments.
If you are using a laminate instrument that has a wood neck or a wooden fretboard, you may still benefit from keeping your ukulele in a humidity controlled environment. Wooden fretboards expand and contract with the humidity, exposing fret ends. Only the plastic & polycarbonate ukuleles--as well as the complete composites of Blackbird have no need of specific humidity control--although you would be well advised to not store a bugsgear or waterman ukulele in your car in the summer!
You want your ukulele to live in humidity levels of 40%-60%. You don't need to shoot for a specific humidity number, but if the humidity of your general area is less than 40%, your ukulele will need a humidifier, and if it is above 60% (that's pretty humid for a place where humans live indoors), you will need a dehumidifier.
I know some people who are not humidifying their solid wood instruments. Maybe that works for them...but they are choosing to take a risk that their instrument could break--and accepting the consequences of that risk. The issue isn't taking the ukulele out of a humidified case, it is where you keep it for the 22 hours that you aren't playing it.
Once the weather where I live turns cold and heat goes on in the house, my humidifiers go into my solid wood ukuleles, and it becomes a weekly exercise to check them (and fill them) with distilled water. Right now I am using Oasis ukuleles, but also throw some Herco humidifiers in the case in the dead of winter, as winter is brutal here.
So...order a cheap hygrometer from eBay or Amazon, which at the least will give you a general idea of humidity, and try to keep your ukulele above 40% relative humidity. Good luck!