PSA: If you have baron and/or 5 drags, and your team is stronger, DO NOT BACK TO BASE.
Force something, ESPECIALLY if the opposing team has several DEAD players.
People really really overestimate the value of finishing an item after an objective like that.
Have a 
and want to back and buy 
? Don't. It doesn't matter if you have 3K extra gold. Stay and do something productive before you back, because backing kills time. I don't care if you're stronger when you finish your Void Staff or your Randiun's Omen, for the love of everything holy, don't waste an opportunity to shove down a tower or even push out lanes in a time where you could be doing absolutely anything else by immediately backing after you grab a baron and kill their team.
"But uncle Lao Fu I can back and finish my 
and my 
and get a 
on top. Then my teamfighting will be even better."
Things you should be focusing on after taking a big objective while the enemy team is dead:
- Pushing lanes
- Pushing towers
- Taking inhibitors if they're wiiiiide open
Things you should not be focusing on after taking a big objective while the enemy team is dead:
- Teamfighting
- Damage output to champions
- Your HP
Why not? Because while they're dead and recovering from the crushing loss of a baron, you guys have the map entirely, 100% to yourself until their team respawns and gets ready.
Yes, it's possible to overstay.
Yes, it's possible for somebody to randomly come out and kill you.
But before you back next time, at least think about doing something as simple as pushing out the waves so they can't just walk down lane because they have a massive wave in top lane.