yes, the heat produced by the ballast when its on makes electronics and solder joints and parts "expand" slightly, then while off they cool and "contract" slightly...so the more you do this the higher the likelyhood of a failure, but keep in mind, cheap ballasts use cheap parts, and probably have cold solder joints that can easily detatch, more expensive ballasts use higher quality parts and are less prone to failures.
It's like a computer...I work in an environment that is very harsh on computer equipment...so in turn we get failures quite a bit...the machines that last the longest are the ones that never get powered off, and I've had several that once powered off, they never worked again