Aviation transceivers, also known as two way radios, can greatly affect your flying. I was surprised to find out how many advantages there are to owning a transceiver.

Some Quick Facts
A transceiver enables one to make two way communications, which is essential to operating an aircraft in controlled airspace, i.e. you can receive (listen) and transmit (speak). Aviation transceivers work on discreet aviation bands. Transmitting (TX) and Receiving (RX) of voice is done on the frequency range 118 - 136.975 MHz. Transmitting requires more power than reception, as the transceiver has to generate an output power of 5W for it to be received by another transceiver 30-40 miles away. Hence, if you are transmitting a lot, as opposed to simply receiving, then the radio will not operate as long on the same charge.
Some transceivers, referred to as NAV + COM transceivers, enable an additional feature which consists of receiving VOR frequencies (108 - 117.975 MHz). Therefore it is possible to track VOR radials and navigate by them.

Backup Radio
One of the obvious advantages is that a handheld aviation transceiver is an excellent backup to the aircraft's primary radio, should this one fail. Unfortunately radios do fail. I have flown a lot of old rental airplanes and, intermittent, is a word I have used a lot to describe the reliability of the installed radios I have used. I have been equally surprised to fly newer aircraft, with newer radios, and found that intermittent doesn't just apply to old radios. The reason for this, I guess, is that radios heat up when used and added to the heat of the sun and/or the engine, and, well they have a tendency to either fail or simply stop working adequately.

Communication Training
If you are just getting into flight training, or simply want to perfect your communication skills, a transceiver is a great tool for improving your listening and deciphering the phraseology used in aviation. I used to follow traffic in the Albuquerque area. I would first pick an aircraft making a call on ground frequency, then follow it all the way through tower, departure and center frequencies, until it was out of range. This helped me greatly and built up my confidence in dealing with B and C class airspace, for which communicating is the cornerstone for staying out of trouble.

Backup Navigation
Transceivers featuring NAV are capable of receiving VOR and Localizer signals. The transceiver, automatically knows when you key in a NAV frequency and will display corresponding VOR information such as radial currently being received.  This is a great tool to have in the aircraft especially if you are flying along in instrument weather (limited or non existant visibility). An alternator failure or a VOR receiver failure in the aircraft is a definite possibility, easy to deal with if you have a backup transceiver offering navigation capability. Not so easy to deal with if you have lost all electrical power and you are now just dead reckoning, one eye on the compass and the other on the timer.

Saving Time and Money
A transceiver is a great way to save time and money. I have gotten into the habit of listening to ATIS or getting a clearance with my transceiver before I even get into the aircraft. I have heard of people that do this while the engine is running (hmmm the hobbs meter too). While I recognize the engine needs to warm up, I do believe that taxiing and run-up provide ample time for this to happen, but then that's just me and my warm climate mentality!

When Stranded!
As much as I dislike the idea of making an emergency landing and being stranded, I do like the idea that once on the ground I can use my handheld transceiver to communicate with overflying aircraft or even use the 121.5 MHz emergency frequency to attract help. I might not want to stay with the aircraft, or the aircraft's radio might simply have been damaged. Why is this such an issue, well, I live in New Mexico, 1.8 million inhabitants for a State the size of Italy, that's pretty barren if you ask me. Not to mention the moutains, forests and other sparsely populated areas of difficult access.

Backup for the Backup!
I am serious. I took my transceiver with me once and actually ended up needing it because the aircraft's radio was scratchy (intermittent). I turned on my handheld transceiver, made one transmission and had to revert to scratchiness. I had forgotten to recharge my transceiver the night before the flight. 5W output was too much juice for what was left in the Ni-Cd rechargeable battery pack. Now I carry a backup alkaline battery pack that I leave in the flight bag, for precisely this eventuality. Oh, and don't forget to get a headset adapter, it's simply too loud to hear or speak on a handheld transceiver while operating an aircraft. You won't hear or be heard very well without one.