Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: How sturdy are the shelves? I am in nursing school and thus have a lot of very heavy textbooks. Just 6 of my books weigh a combined 30lbs.
Document: I don't use the clip but I do avoid loading the upper shelves with heavy objects so that it won't be top-heavy. Easy-to-follow instructions are included. When assembling the unit I have found that it is sometimes difficult to keep all corners and joins square, so some of my units have a bit of a twist which can make it difficult to fit the shelves in place. Still, the bookcases look nice and are functional and affordable.
Since I'm using it to store books, there is a big wasted space a the top that I could have used to store more books. Anyone wanting a bookcase for tall books or tall nick-nacks could simply not use the extra shelf.All in all, it is fine and does the job, and it is sturdy for being so inexpensive.
At this price you expect it to be pretty cheaply made. It was worse than expected. The Ikea shelves at the same price point are made of significantly better materials and are much more sturdy.
I bought 6 of these for my home office to display many books and decor. I lined these up along 3 walls so it gives a nice uniform look. For the price and ease of putting these together, these are well under a budget for having custom built shelving. Since these are made of particle board you have to be careful not to snag them during construction and I highly recommend putting those furniture slide protectors on the bottoms where there is no laminate and you could chip off pcs or snag the carpet.
It took 2 people to put together, instructions were not that easy to follow. Some of the shelves have bowed with the weight of the books. It serves the purpose of what we were looking for which was a inexpensive book shelf to hold my husbands comic book collection. We keep this in a bedroom not visible to guests its great for storage not for looks.
Bought these inexpensive shelves as they were one of the few shelves that coordinated with the oak furniture in my office. I am satisfied with the sturdiness for the price paid.
Suited the purpose of my son. Wouldn't put anything super heavy on it, but it was okay for his needs.
First, this is not fine furniture. It is not meant to be. It is particle board with veneer, not hardwood. If you want fine furniture:  look elsewhere and spend a lot more money. Plain fact of life. This bookshelf is VERY inexpensive, I couldn't find the raw materials to build a book shelf this size from scratch for less, and I mean any material, certainly not hardwood.Second, it is not assembled, it comes as pieces well packed in a box.
This is a very good, cheap, bookcase. It was very easy to put together. Took me 15 minutes. I works well full of books.
I'm using it for my home office, and I was on a budget. Fantastic purchase:  It's sturdy, tall, and looks great.
Answer: I have three of these and they are filled with theological and philosophy books which are large and heavy.  The center shelf is fixed so I put the heaviest books from there down and the smaller  and lighter books on the top two shelves.  For the price they are pretty good.  I do have some stronger Sauder book shelves as well and there is a difference but also a difference when you try to move them.  Remember you have to put them together as they come boxed and you will need a few tools to do so and getting the back panel on straight and well nailed is the KEY to keeping it square and not having any sway when you remove books and replace them.  Again for the price not a bad book shelf.