Sometimes -- but you have to be careful because that releases a lot of nutrients into the tank all at once and disturbs the live sand.
On occasion, I use the sand vacuum to clean up the top most layer of sand rather than churning it up and then doing a normal water change. And on days I vacuum the sand, I do a larger water change.
I usually use a turkey baster and blow the rocks off. Some people vacuum the sand bed somewhat, but as mentioned above, stirring it releases junk into the water and can spike the nutrients. It also depends on how old the sand is
No.
I have 3 systems with sand. 2 have gobies so I don't need to touch it as it's always clean. The other system the rock covers all the sand.
My 35 has 2 yellowheaded sleeper gobies and I do have to move the sand around once a month on the front. They push all the sand to the glass.
Pic 1 15g pic 2 the 35.