Do I Need A Heart Monitor?

I think I'm going to invest in a heart monitor. I've been reading lots of material on why it's good to have one. I'm curious if anyone else is is a fan? Check out this link "Rate not Pace!" and tell me what you think.

• When heart rate stays the same or decreases and your pace is staying the same or increasing, you are getting fitter. Raise your heart rate by 3-5 beats per minute, and evaluate pace. You will be faster.
• On environmentally challenging days with high winds, rain or extreme heat, stick to heart rate as your guide. Limit an increase in heart rate to 5-8 beats per minute from your selected training heart rate. You will complete the event safely and stay mentally motivated. Pace is a small part of your true performance.
• The longer the distance, the more conservative the heart rate. Select a steady-state heart rate, maintain this heart rate and observe your pace. Depending on the distance for completion, if the heart rate begins to increase and the pace begins to slow, decrease the heart rate. Your pace may slow but you will complete the event. If your heart rate begins to decrease and the pace stays the same, increase the heart rate in the last stage, pace will increase, and you will probably pass a few of those who passed you in the early stages of the event.
• Observe, record and evaluate heart rate and pace often. Look for the trends in the data.
• Bang! The race gun blasts and you automatically know “I can run this race at a heart rate of 155 beats per minute (155 is an example — you must select you own heart rate) for 6.4 miles! My heart rate monitor is my guide. I have trained using heart rate and I know exactly the heart rate zone I will use in this race. My heart rate monitor will help me stay mentally focused. I am confident that I will succeed. My pace will be a reflection of my best training.”