Interchangable parts, separate meshes or combined?

So I’m working on a set of assets, where some of which are things like windows, and they consider of the outer frame, the inner frame window part and the lower window part. The lower window part is a separate mesh, as it should be mobile, so it can open up and down. The outerframe and inner frame window part is currently as separate meshes, as currently I have a couple of different frames, and I might have some different inner frames.

However the question is, should I have it as separate meshes, or should I make sets? Is there a problem with having it split up in too many parts? And what is the best way to do it, do you export the frame separate as FBX and the inner frame and lower part in another FBX?
Because since I want to try and keep all the frame textures on their own texture sheet, I would need to use two material IDs if I combine it I think, right?

EDIT: Updating the post to have an example image of what I mean. The first is the full window, and the next three are the parts that it consist of (there is actually a 4th I forgot about, the part below, but never mind that).

You could keep them all separate assets and set up a blueprint with them where you could choose what pieces you want to be used.

Either way you do it, it will probably cost the same performance wise i guess.

Yeah, that was what I was thinking I could do, I was just wondering if there might be some performance issues having lot of meshes instead of combined ones. I had a set of fences and because I was still working with it, it was a load of boxes, that wasn’t merged, and when moving around in the viewport of 3DS Max, the framerate dropped, however, after I merged them all into one object, the performance was much better.
So just wanted to make it wouldn’t be a too big of issue.
Btw, as the glass in the windows might or might not be destructible, should it also be a separate part of the mesh, or can you control it with material IDs? Was especially thinking the lower window, as its a movable object.
Thanks so far. :slight_smile: