Sorry, but It is not clear what you mean by "in real life". You say you understand the theory, so you understand it is another parameter of the wave, just as the frequency is, but you don't seem to have problems with this latter.
I can only guess you need some example from other fields that are more "visually clear". So I propose you to think of the waves on the surface of a lake when its waters are still. When you throw a stone in it you can see circular waves expanding from the point where the stone sank. If you measure the distance between peaks, that's the wavelength.
Of course such nice pictures cannot be taken for EM waves, since you cannot "see" them. At best you could see some effects which can be explained taking wavelength into account, such as diffraction (Wikipedia). Excerpt:
Diffraction refers to various phenomena which occur when a wave
encounters an obstacle or a slit. In classical physics, the
diffraction phenomenon is described as the interference of waves
according to the Huygens–Fresnel principle. These characteristic
behaviors are exhibited when a wave encounters an obstacle or a slit
that is comparable in size to its wavelength.
In that article you can see some equations describing the visual effects caused by diffraction. Many patterns that are produced in the experiments can be related to the wavelength of the waves involved.
Note that diffraction can happen with EM waves at any frequency (RF diffraction), but its effects are not usually "visible" as those caused by light sources.
In this other interesting Wikipedia article on interference you can see also images of effects that depend on wavelength.
In particular, interference between EM waves can have a tangible effect on everyday life with your cell-phone (for example): namely fading. In short: have you ever wondered why sometimes your cell-phone receives a clear signal and, by just moving it a couple of centimeters away, the reception becomes crappy? That's fading in action!
Another practical situation where you must take wavelength into account is circuit theory and Kirchhoff's laws (KLs). KLs are not valid unconditionally, but can be used only under some specific assumptions, namely: the circuit dimensions must be much less than the minimum wavelength of the signals the circuit is going to handle. If that requirement is not met, the results obtained using KLs can be wrong and you'll need to use Maxwell's equations to analyze the circuit. Actually KLs are derived from Maxwell's equation under the assumption that the circuit is much smaller than the wavelength.
That's why microwave circuits are either extremely small or are "funny" because the "components" you see on them don't resemble classic "low-frequency" parts.