Originally posted by bikerider
Usually the chain will 'skip' on the smallest cog under heavy load
I'd add that it can happen in lower gears, too, under hard acceleration/high chain tension situations. If the chainrings are worn, the problem is exacerbated when you put on a new, unstretched, chain.
Even with a completely neglected drivetrain, it's unlikely to be a problem at 1500 miles.