There really isn't a rule about the length of time. The rule is more about the clarity, the amount of sediment, the ABV of the wine, etc.
Usually, I rack every 60 days or so, as long as the wine is throwing lees. This is NOT aging- it's just what you do with the wine. Once it's completely clear, and no longer dropping fresh lees after 60 days, the aging can begin. If it's a lighter wine, not high in tannins or oaked, it can be bottled at that time but it's generally better if it's aged a bit. I'd probably age it 3-6 months, then bottle it and keep at cellar temperatures. If it's a big bold red, high in oak and tannin, I'd keep it in the carboy up to a year or so and probably even do some cold stabilization on it. (The cold causes excess tartaric acid to precipitate out, and then you can rack off of the crystals). You can definitely do it in the bottle, but the wine seems to age more evenly in the carboy.
Sometimes, I just let the wine sit because I'm lazy not because I intended to age it that long. I just bottled my 2008 rhubarb last month. I meant to bottle it last year, but I didn't. It won't harm the wine, and in fact probably helped it, but it didn't need to bulk age that long. It was smooth and clear, with no "hot" alcohol quite a while ago!
Wines that taste "hot" and uneven and a bit harsh can benefit from more aging.