Everyone has their own way of managing stocks. Just use them to what fits your playstyle.
Personally, I'll use them for oki stuff. I don't use D tele much unless I "feel" I can call them out or catch them off guard. D sabers are nice for holding down opponents on their wake up so I can just get away with silly mix up things. I just make sure I have at least 1-2 stocks to finish a combo and go into normal mode as safely as possible. If you know the combos to regain stock, you're much better than I am already.
I'm sure someone else can give a better report on this though…