It's personal preference, but basically edge limits that increase over time, like at 15 you're looking at +-6 months, at 20 it might be + or - 1 or 2 years. At 30 you're probably at looking at 5 years either side of 30.
Once you hit 500 the attraction window is so large it becomes mostly irrelevant, and you're judging more on aristocrical lineage and/or aristocrical diet.
It's only a few more years til 1000 (which usually turns out to be a very dull party with no surprise guests) and by that point you're lucky to find anyone attractive.
There's obviously the old 'hurr durr he's over 2000 so he must be gay now' stereotype, but as far as I can tell, attraction isn't cyclical.
Hope that helps!