I think with polymer notes, they might last until withdrawn by UK standards, but that's a unique factor of how fast they cycle their banknotes out. I think even 5 year old English notes (the paper GBP50 with Watt on it) are at the phase where you have to take them to a bank and replace them with polymer ones.
America has always tried to avoid calling back old notes, likely to avoid creating an upset in places where they're a store of value overseas. This means the old ones can circulate basically forever. I can recall my brother getting a $10 note of the 1934 type in a normal transaction in about 2015, and 1977-series $100s seemed strangely common into the 1990s and 2000s. So the survival rates at 10 and 20 years are relevant for American paper in a way that maybe don't apply in the UK.
America has always tried to avoid calling back old notes, likely to avoid creating an upset in places where they're a store of value overseas. This means the old ones can circulate basically forever. I can recall my brother getting a $10 note of the 1934 type in a normal transaction in about 2015, and 1977-series $100s seemed strangely common into the 1990s and 2000s. So the survival rates at 10 and 20 years are relevant for American paper in a way that maybe don't apply in the UK.