Look, I'm not a pedant.*
As long as you're being reasonably respectful to words (that is, not using them to mean Something Entirely Different), and as long as you don't expect the world to love you when you're bad-mannered enough to break taboos people hold sacred, then it's pretty much Liberty Hall as far as I'm concerned.
Go ahead and start sentences with and or but if it gives you pleasure.
Use an exclamation mark at the end of a sentence beginning gibbons for all I care.
[What was that howling sound?
Gibbons, I think!]
Use so as a conjunction and the chances are I won't even notice.
But even so...let's have a bit of variety can we?
Because if I hear one more person starting the answer to every question in an interview with the word so then I think I just might throw my radio through the window.
Word Not To Use Too Often Today: so. This word was swa in Old English. It meant in this way, or to that extent, or therefore.
*Except sometimes, for fun.