there will be a point in time where ur opponent could be better at handling bananas then u are and or know how to bait or use them against u. in the situation it is most viable to not be desperate for a banana but instead play cautious and smart and be a good banana-less diddy and be the better player overall
I can vouch for this in personal experience. I've played my best friend since Brawl was released, and he has thus had a LOT of Diddy experience. He plays CAPTAIN FALCON, ffs, and yet I still have a VERY hard time beating him because he has learned how to use my Bananas against me (pro tip: on almost any stage, at the beginning of the match, Captain Falcon can run up and catch your Banana before you if you do a standing throw right when the match begins). I REALLY have to mix-up anything I do with a Banana when I play him, simply because he's almost as good at a Diddy player at using them.
Thus, knowing when it is SAFE to pull a Banana definitely is crucial; Back-Throw > Banana Pull is usually a safe option at almost any percent. When you're far away from an opponent, it is PROBABLY safe to pull one, but you have to factor in how fast the character is, or if they are Falco (lasers). If they're fast or Falco, jumping off-stage might not be the best of ideas, even if they're all the way across the stage.
Usually, however, jumping off-stage CAN work. Personally, after seeing ADHD do this in matches, I now do this off-stage:
Run Towards Edge > Full Hop > Smash Banana Pull > Tilt Banana Pull > Jump back towards the stage > Instant Throw the second Banana onto the stage/at the opponent
In my experience, this creates a wall of sorts that many characters can't get through safely.
TL;DR: I'm not going to summarize it, just read it you lazy person