It's no secret that Colorado Springs has two humidity levels - dry and drier. But it might not be commom knowledge that low humidity is no friend to hardwood floors.
What happens when hardwood floors lose too much of their moisture content? Since this post is not for a scientific journal, suffice it to say that hardwood floors do not like to get all dried out. Low humidity in the winter and not-as-low humidity during spring and summer months means that hardwood floors are expanding - when humidity is higher - and contracting - when humidity levels are lower. This excessive "movement" is not healthy for the floor and will cause gaps to appear between boards.
It is not uncommon for me to receive calls from homeowners complaining about gaps in their floor. My first question is: "Do you have a humidifier?" About 90% of the time, the answer is no. I then proceed to explain the importance of maintaining proper humidity levels. The proper level on the low side is 30 - 35%. On the high side you need not worry. 10 - 15% humidity levels are not unusual in Colorado Springs during winter months. So the job of the humidifier is to bring those levels up an additional 15% or so.
There are two kinds of humidifiers that you might consider: whole-house humidifiers and area humidifiers. There are pluses and minuses to both. The advantage to a whole-house humidifier is that there is little to no care involved. And, as the name suggests, it will do the whole house. These humidifiers generally mount to the furnace. When the furnace is on, the humidifier is on. However, there may be times when the humidifier needs to be on to maintain proper humidity levels but the furnace is not on. The best setup is one in which the humidifier can be on whenever it needs to be on, independent of the furnace cycles. Most of these humidifiers allow you to set the humidity level you want to achieve. Even so, it's always good to have a hygrometer (the device that measures humidity) or two in the areas where there are hardwood floors. Setting the humidifier at 30% doesn't necessarily mean that a 30% level will be achieved. If the actual levels are lower, you can change the setting to 35% or whatever it needs to be in order to achieve the desired humidity level.
Area humidifiers are generally cheaper and can be used to regulate humidity levels in a single room or area of the house. The main problem with these humidifiers is that they have to be filled with water on a regular basis. Also, if water is spilled on the floor anytime or every time the humidifier is being filled the boards will warp and then your solution becomes the problem.
All that to say "Yes" you need a humidifier if you have hardwood floors and you want to protect them and properly maintain them.