Speaking of Readbacks...
Not very many professional pilots do it, but a lot of newer pilots readback a lot of information issued to them. In most cases, these readbacks are not required. I'll give some examples.
Often, as a pilot approaches his destination while flying IFR or VFR with flight following, weather information is offered. Most pilots will acknowledge this info, but there are some who, probably for lack of awareness, read back the entire weather sequence. This is not only time consuming for the pilot, but it ties up a frequency (or more than one if the one he is broadcasting on is "coupled" with other frequencies). Altimeter settings do not, as mentioned yesterday, actually require a readback, though most pilots will read these back to ATC.
The only things that require readbacks in Canadian rules are IFR clearances and instructions, amendments to IFR clearances (such as new routings issued, altitudes, restrictions, etc), "hold short" instructions around airports, and any clearances or instructions issued to a VFR aircraft when a readback is requested. Aircraft while taxiing (for take-off or after landing) and aircraft issued landing clearance with a "hold short" restriction (as applied during simultaneous intersecting runway operations) must read back these instructions. The AIP specifically states that taxi instructions need not be readback, with the exception of a "hold short" instruction. Again, most pilots will readback the taxi route as a way of confirming they've received it, and most controllers I've worked with would say nothing to a pilot whether he chose to readback the taxi route or not, provided a "hold short" instruction was readback. If no "hold short" instruction is included, ATC only requires an acknowledgement of the transmission.
Any other information should be acknowledged, so ATC knows you received his transmission, unless the controller tells you he doesn't need a reply. This includes frequency changes, take-off and landing clearances, weather information and so forth. Acknowledgement of a transmission can be made simply by transmitting the aircraft's callsign. Some controllers will want more of an acknowledgement about some things, such as instructions to follow aircraft in the circuit and so on. They normally don't want a readback of which aircraft to follow, but they may want some indication that you see the aircraft you are instructed to follow, for example.
Some references for you are:
AIP RAC 4.2.5, 4.4.2, 4.4.3, 5.2, 6.1
Often, as a pilot approaches his destination while flying IFR or VFR with flight following, weather information is offered. Most pilots will acknowledge this info, but there are some who, probably for lack of awareness, read back the entire weather sequence. This is not only time consuming for the pilot, but it ties up a frequency (or more than one if the one he is broadcasting on is "coupled" with other frequencies). Altimeter settings do not, as mentioned yesterday, actually require a readback, though most pilots will read these back to ATC.
The only things that require readbacks in Canadian rules are IFR clearances and instructions, amendments to IFR clearances (such as new routings issued, altitudes, restrictions, etc), "hold short" instructions around airports, and any clearances or instructions issued to a VFR aircraft when a readback is requested. Aircraft while taxiing (for take-off or after landing) and aircraft issued landing clearance with a "hold short" restriction (as applied during simultaneous intersecting runway operations) must read back these instructions. The AIP specifically states that taxi instructions need not be readback, with the exception of a "hold short" instruction. Again, most pilots will readback the taxi route as a way of confirming they've received it, and most controllers I've worked with would say nothing to a pilot whether he chose to readback the taxi route or not, provided a "hold short" instruction was readback. If no "hold short" instruction is included, ATC only requires an acknowledgement of the transmission.
Any other information should be acknowledged, so ATC knows you received his transmission, unless the controller tells you he doesn't need a reply. This includes frequency changes, take-off and landing clearances, weather information and so forth. Acknowledgement of a transmission can be made simply by transmitting the aircraft's callsign. Some controllers will want more of an acknowledgement about some things, such as instructions to follow aircraft in the circuit and so on. They normally don't want a readback of which aircraft to follow, but they may want some indication that you see the aircraft you are instructed to follow, for example.
Some references for you are:
AIP RAC 4.2.5, 4.4.2, 4.4.3, 5.2, 6.1