Knife sharpening by hand is a skill every man should know. Not that it's easy, but it's a skill that takes practice and undivided attention. The penalty for a split second of looking away or day dreaming is swift and painful. You learn more than just how to put an cutting edge on steel.
I cannot tolerate a dull knife and my EDC keeps a razor edge and I use it. When I do shave I use a straight razor older than my great grandfather that I sharpen. I admit to being a little consumed with knives, so keep that in mind.
Those sharpening guides are a good start to train your hand and arm motions. But after a while you will prefer the freedom of angle and pressure you can get free hand.
FYI, I use diamond hones and leather with fine diamond paste to keep my knives sharp.