Every living being has (mostly unreplenishable) Life Force, Tropebuster is a technique that converts this life force into a deadly attack.
Bob is a robot, using Tropebuster stresses his system and degenerates it beyond repair.
Using Tropebuster increases Bob's lifespan.
Tropebuster is an attack directed at the enemy's life force, causing Rapid Aging in them.
Tropebusting is a practice used to extend lifespan at the cost of permanent losses in power.
Subverted: We see a Distant Finale where Bob is alive and kicking at the venerable age of 108.
But it's only because Bob had become a lich, he actually died from using Tropebuster long time ago.
That is Bob v2.0
Parodied: After Bob use Tropebuster, his friends throw a birthday party for him since he have grown older by about one year.
Zig Zagged: Bob learns the Tropebuster, which is Cast from Hit Points. He (and the audience) thinks that means permanent life force, but it actually uses Ki, which regenerates. Then Bob needs more power for the Tropebuster and has used/is using all his Ki already, so he uses his true lifeforce to fuel it further.
Averted: No attacks cost lifespan to use.
Enforced: "The Hero needs an ultimate attack that can reliably win any battle, but one that he can't simply use everytime."
Lampshaded: "I see your aura grow paler everytime you use that attack."
Invoked: Emperor Evulz curses the Tropebuster somehow, or destroys its previous power source, so that it drains Bob's lifeforce.
Exploited: Emperor Evulz baits Bob into using the Tropebuster repeatedly, while he dodges and taunts - or worse, blocks.
Bob find a way —fair or foul— to replenish his life force after he uses Tropebuster.
Bob refuses to use Tropebuster and finds a way to defeat the villan with a different attack or a different method to power the Tropebuster.
Discussed: "Bob, why would you use an attack that will eventually kill you— literally?" "The years shaved off my life is nothing compared to having to live under Evulz' oppression."
Conversed: "Bob might love his new firepower now, but let's see how he feels in a few years when he's wasted decades of his life overusing that technique".
Implied: Bob is shown to be drained a bit every time he uses it. In the epilogue he is shown to have aged quicker, and is the first one to appear in the funeral montages of the heroes dying of old ag,e despite being the youngest of the group.
Deconstructed: Mastering the Tropebuster skews Bob's world-view. Bob knows that every time he uses it he's closer to death— why should he care about other people's lives?
Reconstructed: Bob can only begin learning Tropebuster after strengthening his soul.