Just a quick thing I decided to do. It started as just a doodle, but I got the idea to see what it might look like through an age progression. This is a female western dragon, from hatchling to venerable old age.
Hatchlings and young adults have dark bar or fleck patterns that help them blend in with foliage to evade predators and to help ambush their prey, like young crocodiles and alligators have. By the time they reach adult stage, their scales (usually) develop a more uniform coloration when it's no longer beneficial to have such camouflage, though older dragons have been known to sport vibrant patterning well beyond their sub-adult stage and well into wyrmhood. One can tell the age of a dragon most readily by noting the amount of bony protrusions cover their faces; the older the dragon, the more hornlets and spikes they are likely to have, though this is not an exact science, as it varies between species and individuals. A more key indicator is the coloration of the eyes, which tends to dull with age at a consistent rate. Scales tend to grey with age, though on a naturally grey dragon, it can be impossible to tell from this alone.
Of course, if you know a dragon well enough, you could always just ask them. A dragon is never ashamed to admit their age; they are proud of long lives, and will even exaggerate it by a few centuries, on occasion.
It is almost impossible to determine what a dragon will look like as an adult from its hatchling stage. Red dragons are usually a mottled brown at hatching, and do not gain their vibrant red coloration until they begin to mature. Green dragons can be born with colors ranging from dark brown to almost black, to vibrant greens streaked with yellow. Blue dragons generally begin green or black, and grow bluer as they mature, much like the reds. Metallic dragons do not gain their shiny, pearlescent sheen until well into adulthood, and their scales become more lustrous and burnished with age.
Will be added to scraps later.