Excessive nesting will add some to file size but it’s not usually the major factor in flie bloat. Excessive nesting just makes it more difficult to work with the object. There is a place for nesting but many users do too much of it in my opinion.
The main contributors to file bloat are overly detailed objects. hoarding unneeded stuff in the file, and huge hi res texture images. Go back through this thread and note the screenshots showing the problems found with the models that failed to open for folks. The thing it seems many folks fail to do is take a look at the larger picture of what they need out of their model. They wind up investing in details that don’t add anything useful to what they are trying to communicate. Often they include details that will never been seen. (No point putting fancy legs under a bed that has a duvet draped over it that totally hides them.)
The 3D Warehouse is a valuable resource of assets for many users but those users need to be discerning in what they choose to download from there. The general wisdom for using objects from the 3DWH in your own projects is to be a smart shopper. Here’s an example from the Warehouse after searching for “bed”.
The first one clearly communicates that it’s a bed and adds less than half a meg to your project. The second one looks nice but it’s quite heavy in the polygon count and the file size is more than 36 times larger than the first. Does it add 36 times more value? The Kelly-Bed is a wee bit lighter in file size although a higher polygon count than bed+7 but with it you get a more interesting looking bed and side tables to boot.
You also need to look closely at the other details provided by the Warehouse. This is for the Kelly-Bed.
For me the Bounds and Distance from Origin raised red flags when I saw them. Following the advice to download components from the Warehouse into a separate file to check them out is always wise. This is what you get when you download it. I added the dimensions and bounding box.
Might be appropriate if you’re modeling a castle at the top of a beanstalk but for most houses probably not. If this bed were going to be used in a normal living space it would first need to be scaled down. Do you invest the time to make the component usable in your model or do you continue shopping or do as you did and just make your own? You have to make that call.
Anyway, learn to keep your files under control and keep them tidy as you go. It’ll save you all sorts of headaches.