It honestly took me maybe 30mins total and that was my 1st time doing it, I was surprised how easy it was. I had been puttng it off for ages cos I was unsure/not confident what I was doing.
You need to know what the valve gaps for your scooter are meant to be set at, mine was 0.04mm, the manual will tell you if you have one.
You just need a socket set to remove the seat and rocker cover, feeler gauge to measure the gap, and socket set to loosen the bit where you adjust the gap. You can buy a special tool to tighten and loosen the pin that makes the gap but I just used pliers, worked fine.
Sounds a lot but its honestly pretty easy if your ok on basic mechanics, read the manual or look on youtube for a vid showing it and just take your time.
Even if you just check them without changing anything, at least then you know your gaps are correct or not and you can get sokeone to do it for you if it needs it and your not happy trying?