What's 1%? Very little right? Well a 1% stretched on your bicycle chain can burn a big hole in the wallet if left neglected especially for higher end bicycle components which cost much much more to replace in addition to the worn chain.
I know nothing about this chain stretch stuff until i see 'valley holes' where the chain rest on the chainring on my market bike. Thus when i see small 'valley holes' on my entry flatbar roadbike i know is time for replacement before the chainrings & cassette are grinded away by the worn chain.
A cycling group's organiser who is also a frugal guy like me shared how to determine chain stretch using a measuring tape - no need to buy fancy chain wear measuring tool:
Picture from: http://www.kronowit.com/bicycling/chainstretch.html
Replacing a chain & learning how to do it (might need chain breaker tool) is a simple skill worth knowing & it pay for itself over a lifetime when coupled with buying cheaper replacement parts from chainreactioncycles.com
Similarly small tiny amounts like buying drinks during meals outside can add up to a sizeable amount over time. Such small leakages in how money is spend can be detrimental to one's financial health over a lifetime.
How many of these small leakages like 1% stretch do you have that is going to hurt you later on in life if neglected?