A friend of mine taught me this tip a long time ago and I have used it ever since. Many people who work around rope on a regular basis will mark their equipment with color coded tape. This helps you identify who the gear belongs to. Also, if you tape a carabiner you can tape the spine toward the gate opening end. This way when you reach to grab a carabiner with one hand you will know which way the gate opens. This is extremely helpful on symmetrically shaped carabiners since it is hard to tell sometimes. The above Carabiner is a pear shape and you can tell that the tape mark indicates the gate opens directly across from the tape.