I had been replacing chains on an annual basis just because "it's time". I read an article that said we could be wasting money replacing chains to early or causing damage because of waiting too long, so I picked up one of these wear indicators. Easy to use and probably saved me a little money because it shows that the chain I would have replaced is still in proper tolerance.
At roughly 1,700 miles I had a chain snap while taking off from a stop. When the chain snapped it broke my front Di2 derailleur and luckily I didn't go down in the process or get hit by oncoming traffic. Do yourself a favor and check your chain when your miles start adding up...
I finally broke down and purchased one of these. I usually replace my chain every 2000 miles. My current chain is approaching that mileage. I checked it with the CC-3.2 and discovered it is no way close to being worn out. I will save money in the long run.
Nice thing to have in your tool box.
Every cyclist needs to know when their chain needs replacing. This tool is an inexpensive tool to have in your box. There are other more costly tools, but I don't know why you would use them when this is more cost effective.
I relube my bike chains every 100 hrs. The bike shop had me replacing the chain annually but when measuring chain wear using this tool I discovered that the chains showed minimal wear ... I could never come close to engaging the 0.5% wear position. I've subsequently started doing my own bike maintenance and use this tool to ensure that my chain wear never becomes excessive.
It doesn't get any easier to use. Just slide it into the chain and you'll know instantly if your chain needs to be replaced or not. It has two sides one for really worn out and one for almost worn out which allows you to plan ahead.