How can you tell whether or not use the furniture that buy on neopets?

You can't "use" furniture in the traditional sense on Neopets. Furniture is purely for decoration and aesthetic purposes within your Neopet's "Neohomes". Here's how furniture works on Neopets:

* You buy furniture in the Neopets Shop: There are various types of furniture for sale, each with different styles and costs.

* You place it in your Neopet's Neohomes: You can choose where to place the furniture within your Neopet's home. This is for decorative purposes only.

* No functional use: The furniture you buy doesn't affect your Neopet's stats, abilities, or gameplay in any way. It's purely for making your Neohomes look nice.

In short, furniture on Neopets is just for decoration. It doesn't have any practical uses.