Okay, these are valid points I will answer best I can.

Creating the model is fine, delete history as you go. But the minute you bind it and paint weights your history will sort of build up again becuase of the skin clusters being created to the joints etc. But then if you delete the history on the bound figure/model it will come out of the bind and all your skin clusters will be lost., and the character will be in the modelling state so to speak. the same goes for blend shapes, if you delete the history on a head once the targets are fed in you'll lose them. So some history is good some is bad.

Also worth pointing out is that if you are rendering a still image for example of a posed figure you may want to delete the history and delete the skeleton entirely to say sculpt a better model in the desired position for you render. It will also make the scene lighter for this type of exercise

Hope Im making sense
Jay