Most of what goes wrong with an order in this category traces back to one of two details. Neither is complicated, and both are on the product page already.
Measure the alcove, not the wall
Skirting, a switch plate or a door architrave takes two or three centimetres you did not plan for.
Wash new bed linen before use
The finish applied for transport softens on the first wash and the colour settles.
Why we publish it this way
For every rack we record the number of tiers and the pair capacity the supplier states, because those two numbers are what a customer is really buying.
A blank field on one of our pages is deliberate. It means the supplier did not give that number, and inventing one would be worse than leaving it out.