.. conversely [perversely ???] I never change strings just for the sake of it.

I own & play far too many guitars to be able to afford to do anything so extravagant.

If I ever break a string through clumsy experimental over-tuning
I'll just root about in a spares box for an approximate pre-used replacement.

My main gigging instrument hasn't seen a new string in the 10 years I've owned it,
and who knows how long before it's previous owner decided to get rid of it ???

I did buy a multi-pack of Newtone 12 string electric sets [10s & 11s] about 12 years ago
which I'd dip into from time to time for any suitable individual strings as required...
But lost the box somewhere in the back storage room
when the junk discarded music gear boxes eventually built up too high.

I only ever play electric instruments
and any time worn dulled tone don't bother me.
I don't like over-bright squeaky sounds anyway,
and usually prefer to roll the tone control off almost completely
for that classic 1960's Rangemaster boosted dark tone.

My instruments stay in tune and sound ok enough to me
playing through lovely hot glowing valves and crankily unreliable vintage germanium transistors.

Our bass guitarist never changed strings either.
The same set lasted about 25 years until a headstrong younger singer bullied him into buying some new ones.
Then he just moaned on for ages about how he'd lost his 'special' bass tone.