On many (most?) wikis, ages in real-person infoboxes are entered a a fixed number. This causes the problem that the number needs to be updated yearly, and will become wrong if it isn't.
To fix this, I have devised an Age template (for example, c:beatles:Template:Age) which takes as its parameters the person's date of birth (in International format, split as year|month|day) which recalculates the number of years since the given date whenever viewed, thus is always correct.
I propose that this be one of the standard templates included whenever a wiki is created.
I don't bother with age at all, since unless you're going to report deaths too (which is unlikely once the interest for a particular show has long sinced waned to nothing, which I'm presently learning), given enough time the age will become ridiculously high. Just slap on their birthday and have done with it, I say.