Guard wires never made sense to me. Skin in contact with or very near the wires would not get a close shave. Skin between the wires would bulge up to contact the blades with uneven pressure. This arrangement seems more likely to cause problems.I started when i was around 16 in 1992. My first razor was the newly released Wilkinson/ Schick Protector. In the commercials they stated he was so sharp, he had to be kept behind bars. I learned the hard way, that you can't trust marketing. The blades seemed rather dull, and even with the blades behind those guard wires, i managed to cut myself quite often, but that may have been through my acne at that time. Probably the worst razor i have used so far. Some time later i switched to a Gillette Sensor Excel, which was a huge improvement compared to the Protector.
For years i tried out every new cartridge razor, of all of them i liked the Wilkinson/ Hydro 5 the most and used it till i switched to DE/ SE shaving this year. Since then i had no more problems with ingrown hairs. I have no intention to go back to a cartridge razor ever!