That's some talent there. I hope your around in 15 years. Those cans of paint are full of carcinogens. You should wear at the very minimum an N95 mask but preferably an organic cartridge respirator to eliminate fumes as well as particulate.
When you do the same job day in and day out its not hard to remember where stuff goes. These aren't artists they are street vendors selling paint doodles like burgers and ice cream... just faster and for more tourist cash..
Is that because of the massive amount of artistic talent?.... Haha. Or.... Is it because the streets are filled with tourists hungry to spend money on any old memory trinket. How many of these so called "artists" sit at home in a studio painting a portfolio for gallery exhibitions..... None!
Stencil painting is not art, and producing a "work of art" takes longer than 7 minutes. It's a job that tourists think is entertaining like any street vendor, €35-40 depending their pitch, 8 per hour do the math, it's a living not artistry....