Let's learn a little be about the beak before we talk about Care & Maintenance.
The rhamphotheca is the horny covering of the beak. It is made of a hard shell of keratin and it covers the bony jaws (the upper-maxilla and lower-mandible). The upper bill is called the rhinotheca and the lower is called the gnathotheca (use that as a trivia question at your next party). The tomium is the cutting edge of the beak and the commisure is the corner of the mouth (there you go, two more trivia answers).
The cere is the soft, thick portion of the upper bill where the nostrils are located. The keratin forms from the cere and grows toward the tip at a normal rate of about 1 to 3 mm a month.
The beak wears down from use ... eating, chewing, rubbing on hard surfaces ... all these things keep the beak in good shape and at a normal length. A healthy bird with opportunitities to chew and rub should not need beak trimmings. Oh, and a normal beak comes to a POINT, it is not blunt at the tip.
Under the keratin covering, the beak has an excellent blood supply and a network of nerve endings which provide parrots with their tactile sensory ability. The most sensitive area is at the tip of the upper beak. For this reason it is not recommended that a novice attempt to trim a bird's beak. Mistakes here will be painful and can bleed profusely sometimes leaving the bird temporarily unable to climb, groom or eat. Such damage may need pain medication and antibiotics and trauma can lead to altering the resulting growth of the beak.
The most common issue we see is beaks growing too long. If your birds beak is inordinately long then you should go to your vet for blood work because this is a indication of liver disease.
Finally, this important excerpt from The Bird Channel page:
Injuries from other birds often involve the region of the beak near the cere and can include punctures, fractures or complete severing of the beak. These require immediate veterinary attention and often involve surgical repair and hospitalization. Owners should carefully supervise their flock and ensure that incompatible birds cannot access each other.
Ways to ensure a healthy beak include:
1) Annual physical examination to ensure optimal health, weight and beak structure.
2) A well-balanced diet, including vitamin-A containing fruits and vegetables.
3) A proper wing-feather trim to allow for safe-landing and turning.
4) Environmental safety prevention including flock interaction management.
5) Appropriate chewing and beak rubbing outlets (wood toys and perches, cuttlebone, mineral block, cement perches).
6) Periodic blood sampling to assess internal health and liver function