versicolour is abit more challenging;)

They will eat as often as they can.  If you are asking how frequently to feed a sling, that depends on the size of the food item too.  The more and bigger the food item you feed, the faster it becomes full, the more time it spends sitting and waiting around to molt.  (BTW, being full is not necessarily good.)
Most T's in captivity are overfed (including some of mine  ).  Part of the reason why many of us feed our T's so much(esp slings) is because we want our T's to grow faster- but that is a choice we keepers make.  Another reason is because we love to see them eat!
When it comes to eating, T's do not require a lot of food.  Their metabolic rate is slow, so they do not need to eat regularly like we do. So long as the butt is about as wide as the carapace it will be fine.  Look at the butt, if it is nice and round, it really doesn't need any more food.  Yes, sometimes they will eat when you give it food but they will eventually stop eating because they can't eat anymore.  Very big butts can be dangerous- think of a balloon filled with water.  The more water in it, the bigger it gets , the easier it is to break.  Overfeeding increases the risk that a T might injure itself.  Just letting you know the good and the bad and you can decide for yourself.
I have a rosie that I have not fed in months and it is doing fine.  When or if you stop feeding your T because you think it has had enough, make sure it still has water to drink.
Good luck with your new T!

I spy with my eye.

@_@new stuff...

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Added on September 18, 2009, 6:52 pmThis Week Update
-Avicularia Versicolour Moulted

-Brachypelma Boehmei Moulted


After Moult,
-Avicularia Versicolour

OBESITY

-White Knee

-Flame Knee

Ventilation is the key
With good air flow, mold rarely grow