What should you be thinking about before you buy wallpaper?

I can’t tell you how many times people have purchased wallpaper and/or border and became upset because their order did not make to them fast enough because instead of ordering all of their supplies first then set a date they set the date then ordered supplies. Because of different things that can happen such as; your desired pattern being on back order, you getting a product then realizing you do not like it once it arrives, your product becomes lost in the mail, etc. you should always order supplies and products first and when you get your product and know that you love the product and it will be the perfect fit for your remodel and have all of your supplies only then should you should pick the remodel date.
Other very important things to consider are:

How good are the walls? If the walls are perfect, a flat finish wallpaper will work or a silk/shimmer effect. If the walls are less than perfect, look for a paper with an embossed or expanded surface texture. For areas that have a lot of use (e.g. hallways), a very plain finish will show marks. A textured or patterned surface is a little more forgiving.
Do you want the same wallcovering throughout the whole house or personalize the rooms? Borders are one way to add personality while maintaining continuity.

How much light do you get in the room? Remember, light colors reflect light and dark colors absorb light. Don’t be frightened of stronger colors as they can be very expressive and add “depth” to a room. Colors affect your mood so think about the mood you want to create. For example, “Greens” are restful, “Reds” are stimulating, “Yellows” are happy and “Blues” are cooling. Think about your own color preferences or pallet – the colors you select for your clothes. Do you want your home to be tranquil and peaceful, or exciting and vibrant? Whatever the mood, it should be a reflection of your personality. Have fun with wallpaper!