I only had to separate the dashboard and the cover it's attached to. I had to unscrew the speedometer rod out of it to be able to move it out enough to access the master cylinder. Definitely more challenging the process to change the fork oil.
When I changed my stock rear suspensions with YSS ones, I did notice the stock ones were old and were very hard to push down while the YSS were very smooth.
When I removed the fork suspensions, they seemed quite smooth already so I was sceptical that changing their oil would help with anything but I did it anyway. The oil that came out was all black and stinky so it's a good thing anyway. However, when I went for a test ride, it did improve it, going on small bumps on the road would jerk the scooter up while it's a lot smoother now. Will be definitely better for the wrists as well. Worth the effort.