Chekov's Gun in Details in the TRPG. Pull-System for Details and Elaboration

Checkov's Gun is a principle by which we can approach details that affect stakes (stakes are things that give set backs or gains to the character). This is using pull system when details come into play in a story. 

if the Player starts talking about their clothes, spending time in the game to elaborate about something that fills out the character like clothes and gives the character depth then the GM will or the Player will elaborate on the clothes when the Stakes are high. 

Basically a Player who spends the Opportunity in scenes to elaborate on details, gets to call on this detail when it is favorable. Calling on the details - if the GM gives hero dice  or bennies or any type of reroll or luck - this allows the roll to be called in a wider variety of circumstance. 

often, in my observation, the Bonus hero Roll just happens. No "Cause", the Players choose to use it and that's it. If the GM wants the story to be more effective you can make it more effective (like rolling a 1d4 or 1d6 with the 1d20 roll) depending on how the player ties in this detail. 

To prevent abuse and the Trope being over played, the gm can limit this to once per Story arc. 

In Christian Camerons Novels (Tom Swan and the Willam Gold Series) the characters Clothes get him into trouble and problems as well as get him out of these problems. 

Not just Clothes, relationships (being nice to the bartender, being an ass to the beggar, etc... ) when the Player choose a scene to elaborate where the detail fleshes out the character this detail will be used later in the Story arc. 

This is NOT a NEW technique. Many GMs use this, except that in my observations they dont use it following the Principles of Checkov's Gun where it will come into play. Checkov's gun exists in most GM's techniques, its just that many of us did not recognize it as a Checkovs Gun until we learn about checkovs gun (there is a Frequency Illusion once we learn something - we realize its been happening a lot and we failed to notice before we learned definitions and concepts)

This is not just for the Party's Gain, but also to the Party's detriment. Often we can make zero-sum choices in the game - Options that have other consequences. When the PC deals with this character instead of another, or chooses one path over another because of Personal reasons (Details) this can lead to how the GM will resolve Hooks (challenges that face the characters) as well as Fumbles (1s rolled). 

 PROBLEM STATEMENT: 

How do you justify Making time for Character detailing? My character likes making pies, and bakes a bunch of pies when he gets down time. How does that fit into my story? 

Stakes (gains or setbacks) modify a detail. if a Detail affects stakes then it becomes more important in the story and more engaging. 

OUTCOME:  

Opportunities to Flesh out the character becomes opportunities to create Details that will come in PLAY later in the game to determine a Hooks and Saves (when the stakes are high).