Chain wear, categorised as chain stretch, becomes a concern with considerable cycling. The put on is removal of materials from the bushings and pins (or half-bushings, in the Sedis design, also, called “bushing-much less”, where the bushing is area of the inner plate) rather than elongation of the sideplates.[8] The strain made by pedaling is insufficient to trigger the latter. Because the spacing from link to link on a worn chain is longer than the 1⁄2 ” (12.7 mm) specification, those links won’t precisely fit the areas between teeth on the sprockets, resulting in increased wear upon the sprockets and possibly chain skip on derailleur drive trains, in which pedaling tension causes the chain to slide up over the tops of the Stainless Steel Chain sprocket teeth and skip to the next alignment, that reduces power transfer and makes pedaling uncomfortable.
Since chain wear is strongly aggravated by dirt engaging in the links, the lifetime of a chain depends mostly on how well it is cleaned (and lubricated) and does not depend on the mechanical load.[6] Therefore, well-groomed chains of heavily used racing bicycles will often last longer than a chain on a lightly used city bike that is cleaned less. Based on use and cleaning, a chain can last only 1 1,000 kilometres (600 miles) (electronic.g. in cross-country make use of, or all-weather use), 3,000 to 5,000 km (2,000 to 3,000 mi) 
for well-taken care of derailleur chains, or even more than 6,000 kilometres (4,000 mi) for perfectly groomed high-quality chains, single-gear, or hub-equipment chains (preferably with a complete cover chain guard).[9][10]
Nickel-plated chain also confers a way of measuring self-lubrication to its moving parts as nickel is usually a relatively non-galling metal.[dubious – discuss]
Chain wear rates are highly variable, so alternative by calendar is probable premature or continued use of a worn chain, damaging to back sprockets. One method to measure wear has been a ruler or machinist’s guideline.[11] Another has been a chain wear tool, which typically includes a “tooth” around the same size entirely on a sprocket. They are simply positioned on a chain under light load and record a “go/no-move” result-if the tooth drops in all just how, the chain ought to be replaced.
Twenty half-links in a fresh chain measure 10 ins (254 mm), and replacement is recommended before the old chain steps 10 1⁄16 ins (256 mm) (0.7% wear).[5] A safer period to replace a chain is when 24 half-links in the old chain measure 12 1⁄16 inches (306 mm) (0.5% wear). If the chain provides worn beyond this limit, the rear sprockets are also likely to put on, in extreme cases followed by the front chainrings. In cases like this, the ‘skipping’ mentioned above is liable to keep even following the chain is replaced, as the teeth of the sprockets could have become unevenly worn (in extreme cases, hook-shaped). Replacing put on sprocket cassettes and chainrings after lacking the chain replacement window is a lot more expensive than simply replacing a put on chain.