UV unwrapping and efficient island packing? I have been trying to unwrap my model after following some online tutorials on this topic, in the tutorial, the instructor said that all sharp edges should be selected and then marked as seams for whatever hard surface models you are making, is what the instructor recommend right? Because right now there are tonnes of small islands as shown in the photo (mainly placed near the boundary after I unwrap the model w/ all sharp edges marked as seams)

On the other hand, what is the 'correct' workflow in packing islands to make the UV map user friendly? Should I place islands that are of the same object together in the UV map to make it more intuitive for users(for example all selected mesh of my model in photo packed together in certain area of the UV map)? Or no one cares about the positioning of these small islands actually (I plan on texturing the whole model later)?
I am just learning this myself, but since nobody else has jumped in, I'll chime in with my 2 cents... I certainly don't mark every "sharp edge". It is good to mark at a sharp edge, but not necessarily "every" sharp edge. I try to mark along lines where I expect the texture to change, and I try not to mark through areas where the texture will stay the same, especially places like the middle of a floor or wall or other large flat-ish surface. The more patterned the texture is, the more obvious it will be if you mark across it (imagine a tiled floor where the middle of the floor has a line through it where the tiles don't line up).

This way it is somewhat easier to texture, and once textured, the seams are not so visible. Of course, this is not always possible without severe stretching, so in cases where I MUST mark across an area where the texture doesn't change (to relieve stretching/squashing), I try to do it at a corner (or sharp edge, like where a wall meets the floor) or a place where it will seem less noticeable (with the grain for a wood pattern, behind an obstacle, in a dark area, etc...).

I don't worry much about where the "parts" land on the UV map. It would be ideal if everything with a matching texture were to land close to each other on the map, but I have tried and not yet found a way to do that without extensive effort after unwrapping (open to suggestions). It's easier to pick through it while texturing than to move things around beforehand.

Like I said, I'm just learning this myself, so let's hope someone with more experience will pipe in with some really good tips.