[Henry Anthony]

Andy,

I strongly agree with all your good words of advice. Constraints are very important. I, however, disagree with the naming of "constraints". I prefer to call them "relationships". The constraints (relationships) define how elements of a sketch relate to one another and how the resulting part relates with other parts (adaptivity). When parts and assemblies are adaptive, it is so much easier - and fun - to explore a variety of design configurations. For me, this is the true power of CAD.

Regards,

Henry