I got tired of the hassle of getting a haircut. I work from home in the country, so I'd have to take a break during the workday, drive 15 minutes, wait another 15 minutes or more just to get in the chair, get the haircut, and then drive home. Typically, it would waste about an hour an half when you consider the "getting ready to go somewhere" aspect.
I bought a RoboCut basic model in 2003 for $45 and a Wahl Trimmer for the neck for $30. You need a vacuum cleaner to use the basic RoboCut, but who doesn't have a vacuum cleaner? I just checked... the basic model is $59 online.
In 2014, I replaced the old Wahl with the Wahl all in one Lithium battery powered model ($35).
So, my cost since 2003 for haircuts has totaled $110. Oh, plus the cost of a hand held mirror.
It's also much easier to experiment with different styles.