[EWillers]

There are factors that are specific to the hand, and then there is the idea of varying one's bet for the sake of "mixing it up".

I first take all the factors specific to the hand into account. These are (collectively) far more important than varying the bet. These factors include: pot size, depth of the money, strength of my hand, position, # of players, what I know about my oppenent(s), etc.

This makes the bet size far more varied than simply 1/2 the pot on an uncoordinated board and full pot on a cooridinated board. Usually, this will provide enough of a betting mixture so as to be dificult to read.

Sure, all these factors are based on rationale, even rationale concievably known to your opponent (save the strength of your own hand).

However, 1) most oppenents are not considering all these things when responding to your bet (if they are you're playing in far tougher games than I) and 2) even if they do take all these factors into account, their assessment of them will necessarily vary enough from mine with the result that making any type of definitive judgement as to the strength of my hand will be rather dificult.

After all these factors are taken into acount I decide whether a splash of artificial "varying" is in order. Usually it's not. But that's just me.