So my bike is getting a bit 'long in the tooth' so my chain/sprocket has gotta be on the way out.

what should I look for when checking it?

I have -1 front sprocket so that little wear indicator on where the rear axle should be is not accurate at all any more.

 

Make sure all of your rollers still spin. Check to see that they are not scuffed looking or burnt looking. Make sure they dont have excess play, side to side or up and down. also, make sure the chain doesnt have excess side travel. If your chain moves sideways as much as it does up and down, it needs to be replaced. There shouldnt be a lot of sideways movement. Anything over 12,000 miles and it a good idea to start checking it more carefully. Mine has 15,000 on it, and it is still good. Im going to replace it anyway, as thats about the limit reccommended. It all depends on how the bike was driven and taken care of. The mileage you can get out of a chain will vary greatly depending on this.


If you do replace your chain, You should also replace your sprockets. Its never a good idea to mix worn sprockets with a new chain, or vise versa.

 

Excellent advice JAS! I would add that there is a service limit of stretch for the chain. Usually is a measurement of a certain amount of links ... 20 - 30 pins. If you have a service manual it should state in there what the limit of stretch is.