Shelving is one of the most useful and simple design concepts for a home, both in terms of practicality and aesthetic value. When considering where to place shelves or shelving units in your home, consider both appearance and function.
Keeping those in mind will help you determine a placement that you can be happy with for a long time to come.
Placement and Precaution
The first factors to consider when deciding where to put shelves are practical ones. The shelves should be placed in areas where they will be conveniently accessible and the least likely to cause any injuries.
Place shelves within easy reaching distance for adults (probably no higher than about 5 1/2 feet depending on who's in your house) and avoid placing them in areas where people are likely to be bending and ducking beneath them (creating a possible risk of bumping heads while standing up).
Place shelves where they're the least likely to get hit by moving objects. Consider any potential shelf spot for its likelihood of getting run into by door swinging open or a rocking chair, or just being bumped by people moving through high traffic areas (like front entryways) or bottleneck areas (like tight spaces between dining tables and walls).
If you have children or pets, consider their actions, as well. Children, especially young children, may reach and grab things they shouldn't if shelves are placed too low, while dogs may run by and knock things over.
Cats can be especially tricky, because they will not only jump directly onto a shelf, they will also be likely to jump onto high shelves from lower furniture or shelves placed nearby.
Visual Effect and Convenience
Once you've ruled out any potential practical problems in the placement of your shelves, consider what locations will make for convenient and attractive placement of shelves.
Placing shelves for the sake of decoration and having a spot to display interesting and attractive objects is best done with shelves at eye level. In fact, the shelf itself should be just below eye level, ensuring that the objects placed upon it are at the best possible viewing height--this can vary depending on the object(s) in question, so aim for getting the middle of the item at eye level.
The other factor to consider when it comes to decorative shelving is where the shelf sits in relation to the other objects in your room or on your wall. Again, the ideal placement will depend on what you plan to place on this shelf, but as a rule, the larger the shelf and items on it, the more central it can be to your decorating, while smaller shelves will look better placed more to the side and in hidden corners or small sections of walls.
Installing shelving for convenience brings other considerations. Look at the layout of your home and consider places where it would be especially convenient to grab items from a shelf rather than getting things from some tucked-away storage space.
Locations that benefit from shelves often include kitchens, craft or sewing rooms and workbench areas, where many tools and appliances are needed at hand.
In some cases, a small shelf can provide a place to put things that would otherwise sit on the floor. An ankle-level shelf in an entry-way, for example, can be a place to store shoes as they're removed upon entry, preventing them from getting kicked around or tossed into messy piles.
Likewise, a small shelf in a bathroom for magazines and other reading material can keep books from being left on the floor.