WOW!!
That's a lot of info on blocks, it'll take me a week to digest it all!!
And even then I may not!!
I appreciate all of the great info, and it looks to me that for now, my best bet is to do as my friend said and save the blocks as their own dwg file so I can change them when I need to.
However, this brings up another thing that I noticed. If I change one of these dwg files, the blocks I've already inserted into a drawing where I'm using them are not updated, at least not until I delete one of them and replace it, or just add another, then I am asked if I want to update the definition. I say yes and it changes all of the blocks...is there a way to do this without replacing or adding one...in other words, is there a command to update the blocks somewhere? (I would just look in the help, but I'm at work not at home where I have the drawings!)
Thanks again to all who chimed in, and thanks to you Craig for taking this in a direction that helped me learn a ton!!