I don't put a specific time on short rests, I just go with what feels necessary in the story. Is there enough down time to recover a bit, or is the situation so pressing that attempting to do so will lead to Consequences? If the former, then it doesn't really matter whether I say 5 minutes or 30, and if the latter then it is similarly a moot point.
This is a style difference.
In one style, the DM says "you have time for a short rest" based on the plot, or is asked "can we try a short rest" and then either provides consequences or not.
Here the short rest is the primary thing in the game, and the DM provides it or withholds it.
In another style, the DM describes the world, and the players work out if they can afford an hour of downtime (or whatever the short rest period is) based off of the world description.
Here, the in game world clock (and events going on) is the primary thing in the game, and the players using up some of it to recover is the thing.
These both work.
But, note that if a short rest is 5 minutes, in the middle of storming a castle (or breaking in) it is plausible you can find a dark corner to hide in for 5 minutes with modest consequences. Doing so for 1 hour or 8 hours is less plausible.
A 5 minute short rest means that anything short of a full on running between battles plausibly has a short rest in it. Cleaning up your weapons and gear can easily take 5 minutes.
A 1 hour short rest means that any reasonably chained sequence of encounters cannot have a short rest in it.
A 8 hour short rest means that any most direct events triggered from the last encounter are likely to be fully resolved by the time the short rest completes.