There is no actual set time system within the RP (eg: one month board time does not equal one year board time). However, all threads on the board do take place at roughly the same time frame - about 4000 years from the Time of Madness (an ancient disaster which marks the beginning of Tryne's calender). The exact year is never specified, but 4000 years from the Time of Madness is the generally accepted.
To ensure continuity, we have one simple rule - your character must not be in more than one thread at once. Why? Your character cannot, obviously, be in two places at once. While it is possible to say that both threads are happening in a different timeframe, this does mess up the continuity a bit. For example - if one of your characters is in two threads, and they, say, lose an eye in one of them - then what about the version of your character in the other thread? You could end up playing two completely different versions of your character. The past, in reality, is fixed and unchangable - it is the same in the RP.
However, if you would like to write about, for example, something that happened to your character in the past - distant, recent, even the present if your character is not currently in a thread - then you can write a short story, also known as an 'un-post' which you can post on the Art and Writing board
Aging Your Character
If you would like to age your character, please mention it on the OOC board first, so we know to change your character's sheet. Also - please be reasonable. As a general rule, don't age your character by more than one level at a time, (it's best not to age them by more than just a few years) and play them for a while before aging them again. And (obviously) don't age them while you have them in a thread at the time. If your character is involved with someone else's character, then talk to them about aging first. The other person may have to age their character if you age yours, and so you should make sure than they're alright with the idea as a result. Most people on the board do not age their characters all that much, and most time-jumps are in the span of months, not years. It's best not to age your character unless you have a good reason, generally.