Morkka mentioned something about how using magic can extend the life of the magic-user. I think I like this.
The aether is a force of creation and channeling it has a rejuvenating effect on the mage. Channeling aether does not fully heal wounds caused by channeling too much magic, but given enough time pretty much anything else can be cured.
Worth mentioning is that channeling magic will correct certain types of genetic defects. This is in reference to the kind of genetic defects that will cause a body harm or pain. If a body is not wounded or ill in some way channeling magic will instead make it stronger and more healthy.
Apart from the above, channeling the aether also increases the lifespan of the channeling mage.
Channeling aether will not cause lost limbs to grow back and it will not cure or prevent insanity or other mental ailments.
It is not yet reliably known how much a life can be prolonged through regularly channeling aether. Some scientists theorize that channeling aether can sustain the physical life of a body indefinitely. However, it has been proven time and again that neither humans nor hobbits are mentally capable of handling lifespans significantly longer than those of their peers.
Many mages simply give up on magic and die of natural causes. Those who do not often succumb to depressions or delusions. Others keep pushing themselves harder and harder and eventually burn out. Some, a few, simply disappear.
A rule of thumb is that once a mage gives up channeling magic completely they will still live on for a number of years roughly equal to half their current age. This assumes the mage has been channeling aether regularly throughout their entire life.
All of the above apply to channeling aether. Weaving does not have the same effect on a mage. The beneficial side effect of the weaving is mainly a greater understanding of the aether; what it is, how it works and how it can be used.